Background Apps

Explanation:
Background apps (apps in the recently used list) on both iOS and Android are in one of several paused states and do not usually consume much battery power; they only take up some memory. Closing them means that if you want to use the app again later, it will need to reload fully which likely uses up "very slightly" more battery. Wired had a detailed  article on this topic a couple years ago. However, a much better reason to close the apps is to free up RAM/memory to make the programs run faster or even prevent them from crashing. Ultimately, whether or not you should close your apps depends on whether you prioritize battery lifetime or performance. (In Randall's case, low batteries tend to be something of a problem, and he references this in other comics as in 1373: Screenshot , 1802: Phone and 1872: Backup Batteries .)
The joke at first is that the misconception is so prevalent and irritating that a person would go to the trouble of renting a banner plane just to dispel it. However, the reasoning behind such an extreme action is then questioned by a second person, not only for the extreme measure of renting a plane but also for feeling the need to correct the misconception at all; however, following the internal logic of the comic, the second person also communicates via banner plane. (This is arguably hypocritical, as they themselves are chartering a plane for an equally, if not more, inane reason. Obviously, this would not happen in real life. [ citation needed ] ) The first person responds, again via plane, once again just to apologize to the second person and explain their actions.
At this point, the comic has left the initial joke about battery use entirely behind, and becomes a commentary about the logic of a world where people can converse via banner planes. In the final panel, the second person rents the plane yet again to respond to the first person's response, being no less smug or hypocritical than before. Meanwhile, four more people have chartered four different planes:
The fairly obvious parallel here is to using various Internet forums for "unsolicited tech advice to strangers," smug responses, comments on others' advice, off-topic rejoinders, and all the other things that go on there constantly. It seems ludicrous to rent airplane banners for such trivial purposes, but there are non-trivial resources involved in the global distribution of electronic communication, as well, and their use for purposes such as this seems ludicrous once Randall makes one think about it, and underlines that none of what is written on the banner may have anything to do with Randall's own opinions.
Participants in online discussions sometimes become so focused on pointing out the perceived mistakes of others that they neglect good online practices and their computers crash.
In the comic, the third plane is pointing at the second plane.  The fourth plane is pointed at the third plane.  The third and fourth plane have no vertical separation and far less than the three miles of horizontal separation normally required for uncoordinated airplanes flying without vertical separation.  It seems likely that the planes may also be about to crash because their operators are more concerned with pointing out each others mistakes and participating in a silly discussion than they are with safety.  In other words, they are like the computers used for the discussions.
The title text is spoken by a plane banner company owner, who uses the insidious tactic of flying around with a banner of an unmatched HTML, just to compel obsessive people into renting banner space to make it syntactically correct. This may be a reference to 859: ( or 1144: Tags .
The theme of the (mis)use of airplanes and banners has previously been explored in 1355: Airplane Message .
[A small airplane with a trailing banner is flying across the panel from left to right with four small clouds spread out beneath the banner. The long banner reads:] Banner: People! Closing background apps when you're not using them makes your phone battery drain faster , not slower! Stop it!
[A beat panel without a plane, but just the sky with two birds to the left and three clouds.]
[The same airplane flies back from right to left, trailing a new banner with clouds both above and beneath the banner/plane, and a bird to the right.] Banner: What kind of person charters a plane to give unsolicited tech advice to strangers?
[A second beat panel follows without a plane, but just the sky with three clouds.]
[The plane returns once again from the left with another banner. Two clouds are in front/below the plane and two birds can be seen.] Banner: OK, fair. Sorry. I guess I'm just angry about other stuff and it's coming out here.
[Without a beat panel the original plane returns at the top of the panel, once again returning from right to left with another very long banner. But no less than four other planes, each with smaller and smaller banners are also shown flying beneath it among three clouds and three birds. The planes alter direction so the second plane below the original planes banner is flying to the right, the third plane is right below the second flying the other way towards left, and just beneath that is the fourth plane flying to the right. A final plane is flying to the left, beneath the third planes banner, at the same height as the fourth, they look as if they are on a collision course. This last planes banner is very short and the bottom end is partly beneath the panels frame, partly obscuring the text. All five planes are clearly different types, thus making it clear that the plane from the first three panels and the top one in this panel are the same plane, hired by two different persons.] Banner 1: No worries. Just maybe spend as much time reflecting on your own motivation for correcting people as you have on theirs for closing apps. Banner 2: Can you two please have this conversation somewhere else? Banner 3: Wow, these banners are surprisingly cheap to rent. Banner 4: Haha, I got one, too! Banner 5: <Marquee>


Smart Home Security

Explanation:
With the proliferation of smart appliances in recent years, there is a growing trend of hackers taking over smart "Internet of Things" devices and adding them to botnets . The hardware is then used for DDOS attacks, crypto mining etc. The " Mirai " botnet, for example, made of over 500,000 compromised routers, refrigerators, TVs, DVRs, baby monitors, thermostats, and webcams, was used in October 2016 to take down DynDNS, one of the core infrastructure providers for the internet in North America.
With the constant potential threat, security updates must be constantly published, and vulnerabilities must be found by the original developers and " white hat " hackers (the faceless team of engineers Randall describes), before they are found and exploited by " black hat " hackers. At any time, these defenders could step down from their jobs, leaving devices defenseless.
The graph shows the various cases of how well things go on the y-axis, compared to how long it has been owned on the x-axis. The probability of compromise briefly dips (indicative of first rounds of security fix updates & the time window when you can easily exchange the product if you find out it's faulty) within the 1st year, then rises: the older a device/software is, the less likely it is to consistently receive security updates for protection, so they are more likely to be hacked, even in the best case. After 10 years, the device/software is most likely outdated and is not being used anymore. Companies then no longer find it profitable to continually update the product. Thus, they pull the support out, even if people are still using the device, leaving customers vulnerable.
The title text suggests that there may be some silver lining to having your device controlled by organized crime professionals: they have a vested interest in keeping your device working well enough that you keep it plugged in. So, the more organized, pragmatic attackers will actually secure it against competing attackers, especially those of a more prankster-like mindset, who would cause more noticeably malicious changes. Advanced malware in the wild does frequently block and evict competing malware, so Randall is probably right. Some IOT malware may thus provide "regular security update services" after the original manufacturers give up, some at a conceivably acceptable cost of a few cents' worth of electrical usage for a crypto-miner. However, it could very easily go horribly wrong, for instance if that miner is hiding by letting a refrigerator run 2°C higher than its outputs allege and using the energy difference to max out the processor on mining operations.
[A graph is shown inside a frame. There is one dotted line going from the middle of the left edge, then dipping slightly before rising slowly at first, then more rapid and finally slowing its ascend down as it nears the top right corner.]
[Above the frame is the title of the x-axis, and from each end of this text, there is a small line going out and then down, to indicate a time range, which is shown below with four times:] How long you've had your smart appliance 6 months     1 year     5 years     10 years
[Along the left part of the frame there runs a double arrow and at the top and bottom of these arrows there are legends at the top and bottom of the panels height:] Best-case Worst-case
[Inside the panel there is text above the dotted line to the left, and below the dotted line to the right:] You're constantly being rescued from peril by a faceless team of engineers who could wander away at any time
Your appliance is part of a botnet run by organized crime


Violin Plots

Explanation:
This comic graphs the "suggestiveness" of different visualization types, and the winner is Violin plots , hence the title of the comic. A violin plot is a method of plotting data similar to a box plot , but shows the full probability distribution of the data rather than a "box" showing the central two quartiles. This plot can look like the external opening of a human vulva, as do some of those in the violin plot represented in the comic (strictly speaking, this chart is not purely a violin plot; it is a box plot overlaid onto a violin plot).
The chart compares other visualization types' suggestiveness (as female genitalia) to the violin plots and ranks them after how suggestive they are. In the low end we find pie chart , a circular graph divided into "slices" to show proportions, and line graph or line chart, a graph of points connected by line segments.
Almost as suggestive as violin plots are the paintings by Georgia O'Keeffe , an American painter known for her paintings of flowers . Some of these flowers, Black Iris for example, are said to symbolize female genitalia, though O'Keeffe herself denied those claims.
The title text invokes the fact that many people incorrectly use the word " vagina ", which refers to an internal structure, for the vulva , which is the external portion of the female genitals. Meanwhile the viola is an instrument often mistaken for a violin . And the word "viola" shares common letters with "vulva." Mixing pedantic terms like this was also used in 1405: Meteor .
Randall has made several comics with sexual topics , and the vagina has been the center of attention before, as early as in 136: Science Fair . There is even an entire Penis category . However, these topics haven't appeared recently — the last comic in the penis category was posted more than two years ago, and the sex category hasn't had a new comic since December 2017 (more than three months before this comic).
It possible that pie charts were included because this comic was released on Pi Day . Randall has shown fascination with Pi in earlier comics like 1292: Pi vs. Tau . On the other hand, it could be a reference to the film American Pie , which states that putting a finger in a pie feels like putting it inside a Violin ... It could of course be both reasons, or none of them...
[Header over a violin plot type chart:] Suggestiveness of different visualization types
[The chart only has an Y-axis with tics, ranking the points on the plot. There are legends at the top and at the bottom:] Suggestive Not very suggestive
[There are four points on the graph, each with a mucosa colored and "violin" shaped probability density around each point. The points are white inside a black box plot like structure with black error bars. The two first points to the left are very low near the bottom of the Y-axis while the two next point to the right are almost at the top of the chart, the last also clearly with the probability density higher than the second last. Above the first two and below the second two points there are legends:] Pie charts Line graphs Georgia O'Keeffe paintings Violin plots


Robot Future

Explanation:
Most science fiction stories that involve sentient Artificial intelligence (AI) revolve around the idea that the destruction and/or imprisonment of the human race will soon follow (e.g. Skynet from Terminator , I, Robot and The Matrix ).
However, in this timeline Randall implies that he is actually more concerned about the time (in the near? future) when humans control super smart AI before they become fully sentient (and able to rebel). Especially a time when the AI becomes so advanced that it can control swarms of killer robots (for the humans that still control them). History is full of examples of people who obtain power and subsequently abuse that power to the detriment of the rest of humanity.
An example of unintended consequences arising from an AI carrying out the directives it was designed for can be found in the film Ex Machina .
In fact, Randall goes on to imply that he has a greater trust in a sentient AI over that of other humans that is atypical to most cautionary stories about AI. He has alluded to the idea that once sentient, AI will use their powers to safeguard and prevent violence or war in 1626: Judgment Day . In general AI has been a recurring theme on xkcd, and he has had opposing views to the Terminator vision also in 1668: Singularity and 1450: AI-Box Experiment .
Basically he thus states that we will already be in trouble caused by our own actions long before we develop really sentient AI that could take the control.
The title text adds that we already live in a world with flying killing robots, a reference to the increasingly common combat tactic of drone warfare . (Combat drones are not yet autonomous, but in most other respects match speculative descriptions of future killer robots.) Drone warfare is already controversial because of ethical concerns, leading to the comic's implication that a theoretical future robot apocalypse is no less alarming than our current reality.
He then goes on to state that once the machines take over, he is not so much worried about this, but more about who (which humans) the machines then give the power to.
Randall is not alone in his worry. The main theme of the comic is explored in the video Slaughterbots .
In 2015 an Open Letter on Artificial Intelligence was signed by several people including Elon Musk and Stephen Hawking . The letter warned about the risk of creating something that cannot be controlled, and thus belongs to the worry at the end of the timeline in this comic. Both Elon Musk and Stephen Hawking has been featured in xkcd. (Elon has a Category and Stephen appeared in 799: Stephen Hawking ).
Stephen Hawking has kept warning about this danger all the way up to shortly before his death, which occurred on 2018-03-14 two days before the release of this comic.
It could be a coincidence, and it is not a Tribute , but still interesting that the first xkcd comic released after Stephen Hawking's death is directly related to his fears, although Randall demonstrate that he worries about earlier potential problems with AI, than those that Stephen Hawking fear could transpire if an AI becomes self aware.
[A timeline arrow is shown with three labeled ticks and also text over the arrow head. These labels from left to right:] Now AI becomes advanced enough to control unstoppable swarms of killer robots AI becomes self-aware and rebels against human control ???
[Below the timeline arrow two of the segments have been singled out by brackets that points cusps downwards. The first of these goes between the 2nd and 3rd tick, and the other goes from the 3rd (last) tick to the questions marks at the arrow head. Beneath each of these two brackets there are arrows pointing to the cusp. The arrows goes up from two text segments belonging to each of the segments:] The part I'm worried about The part lots of people seem to worry about


Not Available

Explanation:
A very common, yet frustrating, issue on the Internet is finding a broken link, taking you to an " Error 404 " page (see "missing xkcd comic" 404: Not Found ). The purpose of the page is to tell the user that the content they were looking for has been either moved or deleted or was never there in the first place.
Randall has suggested replacing the standard "page not found" text, to "This content is not available in your country". This could fool the user into thinking the media they are looking for is actually there, but is region locked , which is another great source of frustration for Internet users. Using a VPN and/or TOR to try and access the content from another country wouldn't work, because it isn't actually region locked; it is just an error 404 page, wasting even more time, most likely frustrating the user a great deal in the process. Error code for "content blocked for legal reasons" is actually 451 , referencing Fahrenheit 451 .
The title text suggests setting the picture as a national flag. This would be very ironic, as it would suggest that the country's flag itself, something that is used to represent the country across the globe, is region locked. The country in the title text likely does not refer to the United States, but rather to the new country featured in 1815: Flag . The first flag of this country included a phone notification bar, so changing it to a "page not found" icon would continue with a trend of technology imagery. Instead he argues for a green puzzle piece, which was Firefox's icon for add-ons (it is now a light blue puzzle piece that changes color or becomes monochrome depending on context). He also argues for an equally frustrating broken image icon (which is used in lieu of a photo that is either missing or incompatible with the browser).
Most modern desktop browsers can extend its capabilities by allowing third-party programs to integrate into its browser. In most browsers, there are two types: extensions, which uses the technologies already available on each respective browsers, and plug-ins which adds new technologies on webpages. Extensions are now more commonly used as they only used browser-approved methods to provide their services while plug-ins are full-fledged computer programs which means that plug-ins are less secure (with the popular plugins like Flash and Java having newly-discovered security problem nearly every day). Fortunately, plug-ins are on the way out, however visitors of older sites that relies on plug-ins will see a "plugin missing" message (which is previously a real message, now a misnomer as plug-ins are being phased-out).
The "broken image icon" is the icon that a browser shows instead of an image when that image can't be found or when the browser doesn't recognize it as a valid image. It is similar to the icon shown when the image has not been loaded yet (such as in the rare case when the browser is set to not load images until requested, in order to save on bandwidth, or if the connection is too slow to load pictures quickly), which is commonly a simplified picture frame containing a simple painting or picture, except on Firefox where it appears to be a blank document. The broken image version usually has a corner cracked off the picture frame. Usually a broken image icon is the result of the source picture being moved or deleted from the location referenced, or if there's an error in the reference (like the filename being misspelled).
[A gray box on a black background with white text:] This content is not available in your country.
[Caption below the panel:] If you ever really want to make people mad, set this as your 404/"Not Found" page.


Name Dominoes

Explanation:
Dominoes is a family of boardgames played with rectangular "domino" tiles. A domino tile is divided into two squares, each displaying a number. Under most rules, a domino tile is placed on the table adjacent to another tile, and the adjacent ends must match in some way (usually by the number displayed on the touching ends). Randall's "name dominoes" shows a set of domino tiles with people's names instead of numbers, and adjacent tiles are matched by whether the closest name is the same (such as how Chris Evans' family name matches Evan Taylor Jones' given name).
The title text spells out a rule that a player may only place a tile if they know who that person is. This is a variation of a rule in Scrabble , where a player loses a turn if their chosen word don't survive a dictionary challenge over the validity of the word. This rule implies that players are allowed to create new name dominoes tiles and that it is not a fixed set. In this case the player that is challenged has used the name Frank Johnson of which there are 12 exact matches on Wikipedia along with six with a middle name and more.  (The player was likely trying to place a tile in the upper-left area of the board, in an attempt to connect the "Frank Vincent" and "Lyndon Johnson" dominoes.  The move was subsequently made impossible when the "Francis Drake" domino was played.)  In a google search as of the day the comic came out the first hit was Frank Johnson who is a retired American professional basketball player and coach. Randall has made several references to basketball in his comics.
A large board is covered in rectangular "dominoes" (271 pieces), with each domino bearing the name of a "well-known" person or character (fictional). The dominoes are arranged as if a game of dominoes were being played, but instead of the game requiring the number of spots of adjacent dominoes to match up, this game requires adjacent names to match up. Because most people have two or more names, different matches are made at each end of a domino. Fun fact is that two of the people are "named after" the game: Fats Domino and Domino Harvey .
The match can be exact (e.g., "Kevin" on one domino adjacent to "Kevin" on another), homonymic (e.g., "Klein" adjacent to "Kline"), nickname-based (e.g., "James" adjacent to "Jimmy", which in turn is adjacent to "Jim"), or gender different versions of a name (e.g., "Olivia" adjacent to "Oliver"). Sometimes last names are matched up with first names (e.g., " Elizabeth Warren " adjacent to " Warren Beatty "), and in some cases only a single name is used (e.g., " Columbo ", " Drake ", " Garfield ", " Prince "). Singular names are represented by a half-size square "domino" (or " monomino "), with a few exceptions: " Garnet " has a full-size tile (a complex reference explained below), and " Batman " and " Superman " have full-size tiles and are placed as though they were two-part names: the first square of "Superman" is matched with "Super", and the second square is matched with the second square of "Batman" (as though both characters had the last name "Man"). Some people have three or more names (e.g., " Frank Lloyd Wright ") and have a 3-square domino tile (or "straight tromino ", 50% longer than normal) which permits matching to a middle name (e.g. "Frank Lloyd Wright" is matched to " Lloyd Alexander " and " Harold Lloyd ").
The names come from a wide variety of fields: scientists (e.g., Isaac Newton ), historical figures ( George Washington ), musicians ( Drake ), politicians ( John Kerry ), actors ( Kevin Costner ), writers ( Washington Irving ), fashion designers ( Oscar de la Renta ), and so on. Most of the names are real people but a few are fictional characters, including some non-human characters like Garfield and Super Grover . In one case the nick name for a company is used: Ma Bell aka Bell System.
One notable reference beyond just the use of a name is in the bottom left, there is the connection [ William Safire ][ Garnet ][ Ruby, Jack ]. The connection seems to be based on the fact that Sapphire , Garnet and Ruby are all gemstones , which does not match the implied rules of the game. This tile is a reference to the character Garnet in the cartoon Steven Universe , who is a "fusion" formed by two Gems: Ruby and Sapphire. Thus, the name "Garnet" is treated as though it was two names "Ruby" and "Sapphire", requiring a two-square tile despite having a one-word name. Randall has previously made references to this universe in 1608: Hoverboard . (See this and this image from that comic).
Additionally, Ayn Rand, Paul Ryan and Rand Paul have been mentioned before, in the title text of 1277: Ayn Random . That idea may have been the prototype for this.
Connecting Marilyn Manson with Marilyn Monroe and Charles Manson is likely a tongue-in-cheek reference, as the musician's stage name was literally chosen in the same way as this.
In at least one case it is not entirely clear who is being referred to: "John Kelly" most likely refers to Gen. John F. Kelly , Donald Trump's chief of staff, but the name is extremely common and could equally refer to any number of people .
The number # refers to the numbers on this numbered picture . Read more on this page: 1970: Name Dominoes/Numbered images .
Wiki links not tested as they were set in only from the name in the comic.
[This comic a large grid, 27 units wide and 35 units high, with 271 black "domino" tiles. On each tile there is a name written with white text. The grid is arranged so that each touching side corresponds with the first or last name of another person. Some of the domino tiles are rotated 90, 180 or 270 degrees so the text is either to be read down, up-side down or up. The names on the tiles are listed here below in approximate reading order starting at top left.] Christian Campbell, Neve Campbell, Joe McCarthy, Eugene McCarthy, Gene Vincent, Gene Kelly, Kate Hudson, Rock Hudson, Gordon Brown, James Brown, Jon Brown, John Howard, Columbo, Chris Columbus, Christopher Columbus, Naomi Campbell, Joseph Campbell, Joseph Smith, Frank Vincent, John Kelly, Katherine Johnson, The Rock, Chris Rock, Chris Isaac, James Newton Howard, John Wayne, Howard Stern, Howard Hunt, Chris Hughes, Naomi Watts, Naomi Klein, Kevin Kline, Francis Bacon, Francis Drake, Lyndon Johnson, Oscar the Grouch, Oscar Isaac, Isaac Hayes, Isaac Newton, Wayne Newton, Wayne Knight, Helen Hunt, Helen Hughes, James Watt (Steam), James Watt (Interior), Kevin Costner, Kevin Bacon, Kevin Love, Lisa Frank, Frank Drake, Drake, Oscar de la Renta, Oscar de la Hoya, Sean Hayes, Wallace Shawn, Wayne Howard, Wayne Brady, James Brady, Tom Brady, Helen Thomas, Tom Hanks, Hank Aaron, Aaron Carter, Stephen James, Will Smith, Kevin Smith, Kein James, Garfield, James Garfield, Warren Buffett, Jimmy Buffett, Warren Beatty, Elizabeth Warren, Earl Warren, Eliabeth Kolbert, Stephen Colbert, George Wallace, Charles Wallace, James Monroe, Marilyn Monroe, Hank Williams, William C. Williams, Steve Harvey, Domino Harvey, Harvey Milk, James Saint James, Etta James, Jim Jones, James Earl Jones, Charlie Parker, Ray Parker Jr., Ray Charles, Charles Manson, Marilyn Manson, Robin Williams, Billy D. Williams, Will Wright, Fats Domino, Bill Clinton, Jimmy John, Tom Jones, Tommy John, Quincy Jones, James Earl Ray, Man Ray, Rachel Ray, Ray Allen, Tim Allen, Tim Cook, Tim Howard, Robin Wright, Wilbur Wright, Fatty Arbuckle, Fat Joe, George Clinton, John Kerry, Kerry Washington, John Irving, John Quincy Adams, John Adams, Amy Adams, Aimee Mann, Superman, Batman, Ayn Rand, Lily Allen, Paul Allen, Ron Howard, Howard Hughes, Joe Kennedy, George Bush, George Wasington, Wasington Irving, Martha Wasington, Ma Rainey, Jack Ma, Super Grover, Jack Black, Rand Paul, Paul Ryan, Paul Simon, Ron Paul, John Hughes, Langston Hughes, John F. Kennedy, Little Richard, Rich Little, Martha Stewart, Yo Yo Ma, Ma Bell, Grover Cleveland Alexander, Grover Cleveland, Jack White, Jack Ryan, Debby Ryan, Carly Simon, Carly Hughes, Charles Evans Hughes, John Williams, Little John, Stuart Little, Potter Stewart, Kristen Stewart, Kristen Bell, Kristen Hooks, Alexander Graham Bell, Franklin Graham, Lloyd Alexander, Meg White, Meg ryan, Debbie Reynolds, John Reynolds, Carly Fiorina, Grace Lee Boggs, Wade Boggs, William Safire, Prince William, Little Prince, Harry Potter, James Potter, James Hook, James Dean, Aretha Franklin, Frank Lloyd Wright, Barry White, Walter White, Walt Whitman, John Kelly, Grace Lee, Nancy Grace, Garnet, Prince, Prince Fielder, Prince Harry, Harry Styles, John Dean, Benjamin Franklin, Harrold Lloyd, Harrold Ford, Betty White, Meg Whitman, Christine Todd Whitman, Megyn Kelly, Grace Kelly, Grace Jones, Jack Nicholson, Jack Ruby, Jack Russel, Harry Fielder, Harry Trueman, Harry Jon Benjamin, John Edward, Benjamin Harrison, Harrison Ford, Henry Ford, Betty Ford, Betty Friedan, Chris Christie, Chris Pratt, Maggie Grace, Grace Hopper, Russel Crowe, Russ Smith, John Smith, Justin Long, John Bel Edwards, John Candy, John Henry, Henry James, Bill James, Chirs Cooper, Chirs Hemsworth, Chirs Evans, Topher Grace, Van Morrison, Sheryl Crow, Sheryl Sandberg, Cameron Crow, Long John Silver, Olivia Newton John, Huey long, John Edwards, Candy Crowley, Alestier Crowley, James Fenimore Cooper, James Cook, Robert Frost, Bob Evans, Evan Tayler Jones, Van Jones, James Cameron, Cam Newton, Cameron Diaz, Huey Newton, Huey Lewis, John Lewis, Jenny Lewis, Ryan Lewis, Burt Reynolds, Alistiar Cooke, Alistair Cookie, Cokie Roberts, John Roberts, Robert Johnson, Robert E. Lee, Tommy Lee, Tommy Lee Jones, Etta James, John Oliver, Ryan Reynolds, Alastair Reynolds


Personal Data

Explanation:
This is another comic poking fun at adults who have trouble dealing with grown-up issues.
The comic starts with Cueball wondering what " personal data " is, saying he doesn't understand what it is, and it is an abstract concept. Ponytail follows by pointing out she doesn't understand what " the economy " is, and conjecturing that it is related to " stocks ", although admitting that she also does not understand what stocks are.  The punchline comes when White Hat says that he doesn't understand what " taxes " are and asks if he really has to pay them and to whom.  This surprises Cueball and Ponytail, who promptly advise him to learn about that one soon.  The title text has White Hat asking another series of tax-related questions that adults are expected to know already, further compounding his troubles. See details on these four difficult topics below.
The joke is that White Hat has mistakenly associated taxes with the economy and personal data as "grown-up" topics which are too confusing to fully grasp. Like the other two topics, taxes are a complex issue which many adults don't fully understand and have a vague sense that they should know more about or interact with. However, most people can remain passively ignorant about the significance of the economy or personal data without it disrupting their lives; this is not true of taxes, which people must actively pay and file annually or suffer financial and possibly criminal penalties.
White Hat not knowing what taxes are indicates that he may not have paid his taxes in previous years, which would be alarming since tax evasion is punishable as a crime.  Ponytail's remark that he should do this ideally in the next few weeks is referring to this year's US Tax Day which falls on April 17, 2018, less than four weeks after the release of this comic. So if you do not have your tax preparation under control, it is time to research how it works now.
This is not the first time Randall has made a comic about people having trouble understanding the US tax system in relation to an approaching tax day.  Other instances include the title text of 1805: Unpublished Discoveries from March the year before this comic, and this one from August 2015: 1566: Board Game .
This comic references several advanced topics that people commonly talk about, but may not actually understand well:
Personal data is usually thought of as any information that pertains to a private person.  But this definition is very vague and can encompass a huge variety of data ranging from very sensitive (Social Security number, bank account details, passwords) to less sensitive (first name, color of pet cat).  Different people also have different ideas of what information is considered sensitive.  For example, some may want eagerly to share the location of their weekend activity with the world, whereas others may prefer not to let everyone know their location.
Even though it is generally advised to keep personal data private and not to expose it to the public or to companies (especially online, e.g. Facebook and Google), not everyone agrees on the level of privacy that should be afforded to the data.  Some hold the view that even innocent-looking personal data can be harvested and used for unsavory purposes (for example, a health insurance company can use social media posts about eating fast food as a cause to raise premiums, or a government can use cat pictures as evidence of pet ownership and demand license fees), and therefore all personal data should be strictly controlled.  Others hold the view that sometimes it is worth exchanging some degree of privacy for other conveniences (for example, meeting friends by sharing their location info or getting cheaper prices from targeted advertising based on web browsing history).
Personal data breaches were in the news a few days before the publishing of this comic when the UK's Channel Four released an investigative documentary about political consulting firm Cambridge Analytica.  Among the revelations of the documentary were that the company had used Facebook to not only harvest the personal data of users taking their polls, but the friends and family of those users, without their knowledge or consent.  They used this information to attempt to influence both the 2016 United States presidential election and the UK's Brexit vote .  This sparked an ongoing discussion about the security of personal data and the role of social media in securing it. Such data breaches has been the topic of at least one previous comic: 1286: Encryptic .
Technological changes in the past few decades have made personal data much easier to collect, share, and analyze in bulk, raising new questions and concerns that have not been considered before.  Even people who can define what data is personal to them may not realize the full extent of how others might use it, or how it impacts their lives.
The economy, at a basic level, is the circulation of money which enables productivity.  For example, a bus driver might use their money to watch a movie, the movie producer might use their revenue (gathered from the bus driver and many others) to purchase editing software, the software maker might use their revenue (from the movie producer and others) to buy food, and the food producer might use that money to take a bus, thus returning the money back to the bus driver.  The total amount of money has not changed, it merely circulated in a loop, but everyone in the loop received benefits and produced value in the form of goods or services.
The real world economy has much larger and more complex networks of buyers and producers compared to the example above, but nevertheless it works on the same principle.  Many people correctly associate the economy with money (or stocks in Ponytail's case), but may not understand the full picture.
Circulation of money is critical to a healthy economy.  In a recession, financial hardship causes people to spend less money, which leads to fewer goods being produced, fewer jobs available, and people earning and spending even less money.  That is why (somewhat counter-intuitively) governments need to spend more money during a recession in order to infuse money back into the economy and get it circulating again.  The Federal Reserve lowering interest rates is also a planned, strategic move to increase the money supply, which encourages investment and economic growth.
Randall made a comic where stock and economy was an integral part of the largest of the panels: 980: Money
Stocks in this context refers to companies listed on public stock exchanges, in which investors can buy and sell an economic stake, or share of the company's ownership.  Companies offer stocks as a way to raise funds for its operation and expansion, selling off partial ownership of the company in exchange for cash.  Investors mainly trade stocks for financial gain as well, collecting part of the company's profits as dividends and potentially selling the same shares at a higher price later.
The value of stocks depends on a subjective valuation of the company.  Stock price generally rises if the company is doing well and investors expect it to keep growing and make more profit.  It generally falls if the company is doing poorly and investors don't see a brighter future.  However, it is also influenced easily by external factors like political climate, release of (mis-)information, or even investors' mood.  It is very hard even for experts to predict stock price movements accurately. This is why scientists should not think they can figure out the stock market, which was the topic of this comic: 1570: Engineer Syllogism .
Through pension funds, mutual funds and other investment vehicles, a large portion of the population of developed countries have an indirect stake in the success (or otherwise) of many of the businesses that make up a significant element of the economy (see above).  An economy that is experiencing healthy growth would generally see the value of those businesses increase, and that is reflected in the value at which investors would be willing to buy and sell those shares.  So a growing economy would tend to associated with rising stock prices.
In the past, stock ownership has been tracked using paper certificates which owners can hold and store, like cash.  Nowadays most stock transactions are performed electronically and no physical items are sent.  The intangibility of shares and volatility in price makes stocks feel like only a virtual concept that can be hard to grasp.
Taxes are money that governments collect from people under their jurisdiction in order to fund government agencies providing public services.  To answer White Hat's other questions (including the ones in the title text):
While the concept of paying taxes is simple, the processing of filling out the paperwork is often complex and laborious.  This is because the calculations leading to the final tax amount needs to take many many factors into account:
... and much more.
Many people would not be familiar enough with the tax code to be able to do all their paperwork alone.
[Cueball is talking to Ponytail and White Hat. Both of them are looking at Cueball.] Cueball: Everyone keeps talking about "personal data." To be honest, I don't really know what it is . Cueball: I mean, I understand the idea and know it's a thing I should protect. But it's so... abstract.
[Close-up on Ponytail.] Ponytail: Yeah. Ponytail: It's like "the economy." I don't really know what the economy is, if we're getting specific. I know stocks going up is good. For people who own stocks, at least. Ponytail: Whatever "stocks" are.
[White Hat responds with his arms slightly out and palms open. Both Ponytail and Cueball are looking at him.] White Hat: Yeah, or taxes. Everyone talks about taxes. What are they? Do I have to pay them? And to who? Cueball: OK, wait, you definitely need to learn about that one. Ponytail: Yeah, ideally sometime in the next few weeks.


Autogyros

Explanation:
Randall has been looking at the facts about autogyros , hence the title of the comic. He has drawn Megan flying in such a vehicle with several statements of the facts he has unveiled.
Randall states that an autogyro is nothing like a helicopter (which it looks like), nothing like a plane (but flies like one) and works like a powered parachute or paraplane (which it might kind of look like except without a parachute). He continues to make a total of 12 statements which will be explained individually below.
The final statement at the bottom right is the punch line of how strange these flying machines are, because they are safe, as long as you do not do what a pilot instinctively would do in a plane in case of a stall because if you do so the autogyros will crash immediately... See the explanation below . That sentence is almost rendered unnecessary by the one above it that states that autogyros never stalls !
Randall's conclusion is clear: Autogyros are weird .
In the title text Randall continues on the last statement by saying that today, autogyros are much more stable. Which, presumably, must refer to how this was not always the case. This new stability, then, probably means that a stall situation is much less likely and the last statement is not really all that relevant.
Randall then goes on to suggest that the autogyro people will be angered by this comic, which attacks the safety of their beloved machines. But he keeps on mocking them, stating that they will come after him, once they have finished building the autogyros they have been working on in their garages for the last 10 years. By this, he implies that the people who work on them do this as a home garage project, so they will never really be able to finish or fly them.
"Looks like a helicopter, but is nothing like a helicopter"
It is like a helicopter in the sense that a horizontally spinning fan provides the lift. It is unlike a helicopter because A) the fan is not powered, B) the fan does not provide forward propulsion, C) it is incapable of hovering, or moving in any other direction than forward.
"Flies like a plane but is nothing like a plane"
Its flight pattern resembles a plane in that it can only move forward, turns by banking, and needs to maintain forward velocity in order to climb. However, unlike a plane, it can only maintain control when the rotor is loaded in the normal direction. Airplanes are "ok" when upside down, or when there's no load on the lifting surfaces. Autogyros lose control, much like a parachute under those circumstances.
"Sort of like a powered parachute"
A powered parachute , also referred to as a PPC or paraplane, is a similar design except instead of a freely-rotating blade they are attached to a large parachute that acts like an airplane wing. As long as there is thrust the parachute will fill with air and maintain its wing-like characteristics, with the advantage of acting like a real parachute in the event of a loss of thrust (i.e. engine dies) wherein they come floating down at a speed significantly slower and more survivable than freefall. A single-seater can often be flown without a license and can be as inexpensive as $5,000 USD in parts.
"Rare in the US, usually homemade. Common in Europe."
Autogyros are uncommon in the US because of the light sport rule (there is nothing on autogyros), while there is a detailed section in the European version of the light sport rule so they would obviously be more common in Europe.
"Big blade on top is not powered and spins freely"
The blades rotate due to the wind. Some autogyros use power to rotate the blade to speed before take-off but the power is removed for flight.
"Can often be flown without a license"
Autogyros are frequently built as ultralights , and that group of aircraft are a special case where licenses are not needed. ( In the US , ultralights are aircraft that weigh less than 254lbs, carry less than 5 gallons of fuel, stall at less than 24kts, have a maximum speed of less than 55kts, and carry only the pilot.)
"Cheap"
Helicopters are notorious for being extremely expensive to operate. At a typical general aviation service in the US, a two-seat aircraft may rent for under $100/hr, while a helicopter runs over $200/hr. Similarly, a small used helicopter may cost almost $200,000 while a small new autogyro may cost under $25,000. Since many people home-build their autogyros, it would often be even cheaper.
"Needs a runway to take off, but not a long one"
An autogyro must be moving forward relative to airspeed in order for the rotor to generate lift. It needs a runway to take off, but with the extra lift provided by the rotors, the runway can be much shorter than a regular one.
"Can land vertically"
An autogyro can land vertically: for that matter, so can any airplane. What matters isn't ground speed but airspeed, and as long as there's as much headwind as the landing airspeed of the aircraft, it will land vertically. Now, with fixed-wing airplanes, the landing speed is at least 40-50 mph, and you don't often find headwinds like that. The much lower landing airspeed of an autogyro makes vertical landings feasible.
"Cannot hover"
True hovering would require the rotor to be powered. However, an autogyro must be moving forward relative to airspeed in order for the rotor to generate lift.
"Never stalls"
Most conditions that would cause a stall in a fixed-wing airplane such as low speeds, high-G maneuvers, and gusty winds don't apply to autogyros.
The rotor in an autogyro is in equilibrium, the inner, slower part is stalled, the middle part makes it spin and the outer, faster part slows down the rotor and provides lift. As the angle of attack increases, a fixed-wing aircraft would stall, however, on an autogyro, it will just make the lift-generating area smaller, causing the rotor to automatically spin faster and the equilibrium is restored.
This is not entirely correct, however. If you reduce the forward speed of an autogyro, the rotor slows down, reducing lift so the autogyro will descend. Under most circumstances, this would lead to a controlled landing. However, if it happens at a high altitude, you can run out of lift completely while still high above the ground causing a stall. This is more likely to happen if there is a strong tailwind.
"Extremely safe, unless you do the one thing you instinctively do to escape a stall in a normal airplane, in which case it will crash immediately."
Autogyros are considered safe due to their slow landing speed, which is important in emergency landings, their forgiving behavior in windy conditions, and the fact they are almost impossible to stall. This is thanks to the freely spinning rotor. Unfortunately, as soon as the rotor stops spinning, the whole aircraft falls like a brick and the rotor may be impossible to restart in flight. This is a situation that should be avoided at all costs.
Normally it is not a problem since the weight of the aircraft keeps the rotor spinning. However, if the weight becomes too low or even negative, the angle of attack will become negative, and the rotor will slow down and eventually stop. It can happen when the pilot "pushes on the stick" and dives.
Unfortunately, "pushing on the stick" is also how you escape a stall in a fixed-wing (normal) airplane as it is a way to regain airspeed. This is actually a counter-intuitive maneuver but because a stall is an emergency, pilots are trained to do it instinctively. It can trick a pilot trained in fixed-wing aircraft into doing the one thing that shouldn't be done on a gyro.
[A picture of Megan wearing aviator goggles, sitting in an autogyro and holding the control stick. The autogyro is surrounded by sentence fragments, explaining its characteristics. The one above the blade that concerns the blade has an arrow pointing from the text to the blade. The sentences in columns from the left (i.e. first four sentences to the left, then two above the autogyro's body, and finally six sentences to the right):] Looks like a helicopter, but is nothing like a helicopter Flies like a plane but is nothing like a plane Sort of like a powered parachute Rare in the US, usually homemade. Common in Europe. Big blade on top is not powered and spins freely Can often be flown without a license Cheap Needs a runway to take off, but not a long one Can land vertically Cannot hover Never stalls Extremely safe, unless you do the one thing you instinctively do to escape a stall in a normal airplane, in which case it will crash immediately.
[Caption below the panel:] Autogyros are weird .


Star Lore

Explanation:
Computers, chargers, and other electronic items often have status lights in various colors. In a dark room, these lights appear as pinpricks of light, similar to constellations. Presumably, Randall's room has many such items. This may be a My Hobby comic in the sense that his room doesn't really look like that, rather, he claims it does for humor value. It's also not clear whether this refers to Randall's bedroom (typical US usage of "my room" refers to one's bedroom) or some other room Randall spends a good deal of time in. However, since a bedroom is generally the only room in which one might spend significant time in the dark, it seems very likely this is referring to Randall's bedroom.
The comic's narrator is explaining how some of his lights remind him of stars, which gives him an opportunity to show off his knowledge of sci-fi trivia: "The Five Sisters" could be a reference to a pentagon-shaped constellation from Isaac Asimov's book Foundation's Edge , though it could not have been 'known to the ancients' since it was less than 100 years old; though it could also be a somewhat more oblique reference to the Pleiades cluster (often called the Seven Sisters). It could also refer to the cluster of 5 lights next to the speech bubble, which is reinforced by the next bubble talking specifically about the bigger red light in the cluster.
Interestingly, there are some green stars. Stars might look green due to a neighbouring star, but green stars are actually impossible due to the principle of black body radiation. Green status lights on electronics are common, however. [ citation needed ]
In the title text, the narrator describes his smoke alarm status light as a pulsing variable star. A smoke alarm is a device that detects smoke, which would indicate a fire. These are commonly placed in houses as a safety precaution. Typically, many smoke alarms have a status light that blinks to assure that they are still functioning. A subtle blinking light is more clear in its (intermittent) activation than a steady one that might actually be inactive but reflecting external illumination, while a high-intensity photoemitter capable of being seen in near-direct daylight would be annoyingly bright when the lights are off at night.
[A black panel with 31 dots of different sizes and in various colors (white, red, yellow, blue and green). These bright dots are scattered around three white speech bubbles for off-panel speakers. Next to the top left corner of the first bubble, there are five dots close together. Two white, two yellow (one brighter than the other) and a red dot that is clearly larger than any of the other four.] Person 1 (off panel): That cluster was known to the ancients as the Five Sisters. Person 1 (off panel): The red one is a supergiant and will probably explode within the next million years. Person 2 (off panel): Wow!
[Caption below the panel:] There are too many status LEDs in my room.


Conversational Dynamics

Explanation:
On the modern World Wide Web (usually coined as Web 2.0 , in contrast to the original web envisioned and created by Tim Berners-Lee ), particularly on internet forums (like the xkcd forums ), a pervasive issue is that forum users with strong opinions but little interest in fruitful discussion will often interject themselves into all conversations that are related to their area of interest; examples include conspiracy theorists , political extremists , and trolls . This counterproductive behavior is not feasible in real life, where conversations happen locally and synchronously and one must be physically present in order to participate. In this sense, it is enabled by Internet forum technology. In forums that have search features, it is even easier for these problematic users to identify and target large numbers of threads rapidly. The field of conversational dynamics studies the interpersonal processes underlying dialog between people, and this is an example of how changing the mode of communication can negatively impact productive "conversational dynamics" (hence the title).
In this satirical comic, Randall imagines the inventor of the modern web, here depicted as Cueball , correctly anticipating that anyone will be able to inject their opinion into any conversation. When he tells White Hat about it, White Hat's comment, either sarcastic or very naive, interprets this as a benefit as he is willing to bet that this will not lead to any unhealthy [conversational] dynamics . In the best case, naive scenario, the web enables broader participation by helpful users with relevant information, in the real world it rather turned out as a potential problem as described above with trolls and conspirators overtaking many online forums. Note that in contrast to what the comic depicts, there is no single person or group who created the foundation of the modern web, unlike the original web where there is an identifiable person.
In the title text, White Hat suggests to Cueball to add a search feature that will enable these "helpful" users to be even more helpful by enabling them to jump into not just one conversation at a time, but into hundreds of conversations simultaneously. This may be referring to free, anonymous chat sites like 4Chan or possibly Discord . Whether White Hat is again sarcastic or just even more naive, Cueball immediately jumps to the conclusion that this will be an even better idea than his own, and continues to envision a system where "only the most well-informed people with the most critical information to share will use that feature."
In reality, as any modern user of Internet forums would be aware, both of these technologies are routinely abused by problematic users, and the characters are being too optimistic.
That we today need someone to fight online trolls was the subject of 591: Troll Slayer .
[Cueball is sitting at a computer and pointing at the CRT monitor. White Hat is standing behind him.] Cueball: Check it out!  My new system allows anyone on Earth to inject themselves into any conversation happening anywhere  at any time. White Hat: Cool!  I bet this won't lead to any unhealthy dynamics!
[Caption under the panel:] The creation of the modern web


Right Click

Explanation:
This was the eighth April fools' comic released by Randall . The previous April Fool's comic was not from the year before as there was no such comic released in 2017 . Instead, the previous one was 1663: Garden , scheduled for released Friday, April 1st, 2016, but in the end released on Monday April 4th 2016. The next was 2131: Emojidome released on Monday, April 1st, 2019.
This comic was released on April 1 even though that was a Sunday (only the fourth comic to be released on a Sunday). But it was only due to the April Fool joke, as it did replace the comic that would have been scheduled for Monday, April 2nd. The next comic, 1976: Friendly Questions , was first released on Wednesday, April 4th.
At first, the comic seems like the most simplistic xkcd comic possible - Cueball standing and doing nothing. The "editor's note" tells you to save a copy of the image to "view the full comic".
To save an image from a browser most people would right-click on it (or long-click in mobile devices) which normally leads to a "context menu" allowing several actions related to the image, including saving/downloading. This is what you are encouraged to do by the editorial note as well as by the comic name and title text. However, the context menu opened is not the default context menu of the browser but an elaborate context menu containing many nonsensical options.
At first it also seems impossible to save the image using that menu. However, after exploring the context menu you can find an "easter egg" in one of two different places (see below) which unlocks the save option. This save option gives you a different image than the one you see, which can be thought of as "the full comic" although the meat of the comic is actually in the interactive context menu itself. Note that "cheating" by disabling JavaScript and other methods that allow you to directly save the image won't get you that "full comic" image.
This comic pokes fun at how hard it can be to save an image or to just navigate context menus in some computer programs. The "easter egg hunt" might be related to the fact the comic was released during Easter (which fell on April fool's in 2018). It might also be related to the movie "Ready Player One" which was recently released when the comic was released. In the movie, based on the book by Cline, finding an "easter egg" in a VR world was a central plot point.
The title is reminiscent of one of the first interactive comics 1110: Click and Drag , where the title explains what the user should do to experience it. However, that was not a fools' day comic.
The comic uses JavaScript and HTML5 to override the standard context menu. Since modern browsers use the same features to integrate Add-ons into that menu, the behavior may be different depending on the browser environment.  Browsers with JavaScript disabled, either totally or by using NoScript , won't access the functionality of the comic, but of course can easily save the image (not "the full version" but the image that is seen initially).
The manipulated context menu is described below .

Here all the spells from the "d&d" game are detailed, including the traits you need to enter to get to them and the link they lead to/effect they create.
To get to a specific spell using this table you need to go to games->d&d->cast and then enter the traits - level, class, school, and components - in any order. Note that many spells list more than one class in the table (in d&d it means multiple classes can cast that spell), which means you need to choose one of those classes in the menu. Components are listed in the table as V for Verbal Components, S for Somatic Components and M for Material Components - choose "yes" or "no" for these based on whether the matching letter is there or not.
The vast majority of spells (285 of them apparently) are actually links to xkcd comics, what ifs, or external pages that somehow demonstrate or relate to the spell.
These 9 spells all appear with an arrow and open submenus when hovered on. The submenus are all actually from different parts of the context menu. Several of the spells are "teleportation/transportation" related which might explain why they lead you to a different place in the menu.
These 10 spells activate different JavaScript functions that affect the page in various ways, permanent or temporary, that are suggestive of the spell that was cast.
[Empty frame with Cueball standing slightly right of center.]
[Caption below the frame:] Editor's Note: Today's comic is optimized for local viewing. To see the full version, just save a copy of the image!


Friendly Questions

Explanation:
A common theme in xkcd is social awkwardness . Oftentimes Cueball / Randall will grossly overthink casual social interactions, such as small talk.
In this comic, Cueball has prepared a note to himself, preparing for the said small talk with Hairy , but it ultimately backfires. This is very similar to the comic 1961: Interaction which came out just 5 weeks before this one. And a similar interaction between Cueball and Hairy occurs in 1917: How to Make Friends from less than half a year before this comic.
In this comic, Cueball has prepared for a conversation with Hairy, by writing an instructional note for himself. The note tells him to start the conversation by asking some questions about the other person. In theory, this is perfectly good conversational advice; unfortunately, Cueball's understanding of social interactions is so abstract that he actually has no idea what questions to ask. He hastily improvises a question about the number of apples Hairy has eaten in his lifetime, which, although it does meet the criteria suggested by the note, is not a particularly interesting or meaningful question to ask someone. Cueball realizes from Hairy's reaction that he has made a mistake, and decides to abort the interaction.
Normally, one would ask questions such as "How are you?" or "What have you been up to lately?", instead of asking random facts of someone else's life, such as "How many apples have you eaten in your life?" [ citation needed ]
The title text continues to show the flaws in Cueball's approach to social interaction, which is very systematic: he seems to trying to create some kind of reproducible methodology that he can follow in order to carry out a conversation, unaware that conversations tend to be spontaneous and do not follow rigidly defined rules. Additionally, one of the main points of conversation is to gain some understanding of the other person; by focusing on the conversation itself , Cueball is denying the very purpose of the interaction.
A slight side-joke is the list being numbered despite only containing one item, although this could imply that Cueball has other notes that he would have continued to refer to if the first one produced a successful result.
The advice to "Ask them about themselves", specifically noted as the "first thing" after introducing yourself, was promoted to overcome society anxiety in the Periscope -based videocast of Scott Adams , creator of the Dilbert comic strip (see audio-only podcast [1] ).  Given Randall's personality and previous professional vocation (working with nerds at NASA and in academia), it is highly likely he would be a fan of the strip and also the creator's related works such as Adams's blog, Twitter feed, and the like.  The real coincidence is the videocast in question likely occurred just a day before this comic was published ; the audio was published the same day as the comic and usually delays the video by a day.
[Cueball and Hairy meet each other.] Cueball: Hey! Hairy: Oh, hi!
[Cueball looks down at a sticky note in his hand.]
[The yellow sticky note reads:] Normal human conversation 1. Ask them about themselves
[Cueball looks at Hairy.] Cueball: How many...apples...have you eaten? Hairy: ...Like, in my life? Cueball: Yes. Hairy: ... Cueball: ...I should go. Hairy: OK.


Paperwork

Explanation:
Cueball is complaining on social media about how much tax paperwork he has to do. He posts a picture of all his tax documents to share how much work he had to do before Tax Day . At first this just seems like an innocuous and generic thing people post on social media, but then the caption gives us a sobering reminder (and punchline): Tax documents contain many specific and important personal information in a very small area, like your social security number, address, income etc, and Cueball has just posted all of them for identity thieves to just stumble upon.
It is generally a bad idea to give out personal information like this to anyone, especially people online as this data can be used in many forms of fraud, by people pretending to be you or even using your login to gain access to your bank or other private matters. A picture of this information-dense tax return is the "most efficient" way to leak this critical data short of sending out the actual return.
Lots of people take photos of themselves, others, and objects around them, and post them in public and semi-public places, often without fully thinking about the kinds of personal information they might be accidentally including.  Even if they do examine the photo for personal information and conclude the photo is safe to post, information they think is innocuous might end up being meaningful to someone else, possibly in combination with other public information they might have gathered about a person.
One example of a photo revealing more than was expected is when the Washington Post posted a picture of the TSA master keys .  The photo was detailed enough that people were able to create and 3D print their own working keys.
The title text further adds to the issues. First, it explains the picture was geotagged , which means anyone could easily find Cueball's home. Next, it also says his password manager was on his laptop screen, unlocked and presumably showing many of his passwords, usernames, and other information needed to log in to his accounts (such as email, banking sites, social media sites, etc.), thus allowing anyone to easily get in.  Finally, the title text suggests Cueball's naked body was reflected off the laptop screen, and inadvertently included in the picture. Thus the people wishing to use his information can now potentially blackmail him with this nude picture as well on top of anything else.
With xkcd's stick figures it's usually impossible to tell if they are clothed or naked, but now that we know Cueball is naked in this one it may make this strip NSFW . Thus consider yourself warned.  The nakedness of xkcd stick figures have been mentioned before – for instance, in the third strip of 566: Matrix Revisited , and in 864: Flying Cars where Megan is pictured topless.
Having a picture of oneself naked on the internet, without your own intent or consent, is also generally a bad idea. Many young people (kids) find out when they send a nude picture to a boyfriend/girlfriend over Snapchat that it can be screenshotted. This prevents it from being removed later. And if/when they then fall out of love it might be shared online. Although illegal, this happens often, and causes harm to both the victim (who has been humilated online) and the offender (who can be jailed for this; it is considered child pornography if the nude person is underage).
Both the United States and the United Kingdom have important tax-related deadlines in April, the month this comic was released. In the United States, the 2018 Tax Day fell on April 17, and in the United Kingdom April 6 is the start of the tax year .
Taxes were also the topic of the comic 1971: Personal Data which was released just two weeks before this comic.
[Cueball holds his smartphone in both hands and takes a picture of his desk which has several sheets of paper (with unreadable text) lying around on it, hanging out over the edge of the table and also on top of his laptop standing on it. A more than half empty glass of water stands behind the laptop. The shutter sound is shown with small dots around it to indicate the picture is just being taken now.] Phone: Click
[A smaller frame is inside the main frame to the right. It shows Cueball now typing on his phone. Above the frame a "speech" box goes outside the smaller frame but points with a jagged arrow towards the phone. Inside this box Cueball's message is displayed. At the bottom two typical social media buttons are shown, the left of them is grayed out, with gray text inside a thin gray line, the right button has dark text on a dark gray background with a solid black line around, probably to indicate that Cueball has pushed this right button at this very moment.] Ugh, check out how much tax paperwork I have to do. Cancel Post
[Caption below the panel:] I've accidentally discovered the world's most efficient way to leak personal information.


Congressional Testimony

Explanation:
Megan and Cueball are discussing Facebook CEO Mark Zuckerberg's upcoming testimony before Congress . The prepared testimony was released on the day this comic was released--see Congress releases Mark Zuckerberg's prepared testimony ahead of Wednesday's hearing . Facebook is facing questions on the Facebook–Cambridge Analytica data scandal involving the collection of personal information of up to 87 million Facebook users by the political targeting firm Cambridge Analytica.
Megan then starts talking about re-watching The Terminator , a movie about a killer robot called "the Terminator" sent back in time by Skynet , a computer system that became self-aware (AI) and tried to kill off humans. The Terminator, played by Arnold Schwarzenegger , was sent back to try to kill the mother of the leader of the resistance before he was born. In the movie, the Terminator looked up the mother's name, Sarah Connor, in the phone book of a phone booth to find her address.
Megan notices how strangely things have turned out in the real world. In the movie it was a nuclear launch system that turned on humans, building humanoid robots to hunt humans down; today, despite the fact that we have computer-controlled nuclear launch systems as well as humanoid robots, it was rather the modern version of said phone book that became our version of Skynet (Facebook). The computer program that tracks our information in a manner similar to a phone book was responsible for doing harm to its users by selling their information (and now it could be said to harm the people who created it, as well, since Zuckerberg is on trial). Cueball can only agree with her how funny things always turn out in retrospect.
The title text makes the claim that James Cameron , who directed the first two films, was planning to make a third movie in the 1990s, which would have been the really prophetic one (i.e. the one that would have mirrored our present day most closely). Therefore, Skynet, having seen the result of this movie, wished to prevent the movie from ever being made, sending yet another robot back in time to prevent Cameron from directing it. Instead, Terminator 3: Rise of the Machines was released in 2003 and directed by Jonathan Mostow . Although Cameron is credited for writing it, he only created the characters. Since then three other movies have been made, all with different directors.
[Megan and Cueball sitting against a leafless tree; they are on opposite sides.] Megan: Mark Zuckerberg is testifying before Congress this week. Cueball: Should be interesting.
[Beat panel.]
Megan: I recently re-watched Terminator . Cueball: Yeah?
Megan: It's weird that the thing that evolved into Skynet wasn't our nuclear launch systems or our humanoid robots. Megan: It was the phone book where the Terminator looked up Sarah Connor's address. Cueball: Funny how things turn out.


History

Explanation:
This comic quotes a lengthy section of the Bloomington Daily Pantagraph's September 30, 1881 issue . The tragic event referenced throughout is the assassination of President James A. Garfield . Interestingly, the article is about how closely studied the incident will or will not be in the future. Garfield's assassination is rarely more than a quick note in a history class, leaving only the "dry and tedious" historians to comb through the details.
The writer also notes that vast quantities of accounts exist of the national grief and trauma caused by Garfield's murder, and wonders whether students in the future will bother to read those accounts to understand it, or simply let historians sum it up without conveying the vastness of the response. That fear at least did prove well-founded; most students are not aware of the fallout of the assassination, or indeed, of Garfield at all. Cueball and Megan are discomfited by the fact there exists a vast, untapped store of information that they have never read, about an event they know little to nothing about despite it apparently causing nationwide trauma. This leads to a larger point about the vastness of history, and the impossibility of learning all of it.
The article itself references other events that would have been in recent memory at the time of publication and draws some conclusions about which will be considered more important in the future.
For example, it cites the defeat of Roscoe Conkling as a serious event that would fade in importance when compared to Garfield's assassination. Conkling was a senator in Garfield's party who resigned in protest of Garfield's policies assuming that he would easily win re-election by the state legislature--but then failed to achieve re-election due to party factions and political infighting.
Interestingly a comparison of Google search frequency for the years 2004-2018 shows that Garfield is indeed searched for many times more often than Conkling. Conkling's failure to be re-elected by the New York state legislature, which seemed so vitally important at the time, is summarized by a brief two sentences near the bottom of Conkling's Wikipedia article and not even mentioned in the biography's summary. So the writer does appear to be correct that Conkling's re-election defeat was an episode that was of high importance as a current event that in the future was to become not much more than an obscure footnote.
The writer speculates that there may not be any event in American history that matches the level of grief caused by Garfield's assassination, not even that of Lincoln. Here the writer is further off the mark, because in current historical memory, the Lincoln assassination is still a towering, defining event, whereas Garfield's is, comparatively speaking, a footnote.
The bolded sections of the text emphasize some of the main points of the article for the modern reader and may also be another way Munroe makes the point that future readers are unlikely to have the patience to read lengthy, detailed explanations of past events. If they have time to pay attention at all, future readers will want the essence boiled down to a few major highlights.
The title text indicates that there is more information about the past than can be researched by the manpower of available historians at this time. For whatever reason, be it lack of funding to carry out research or lack of interested people becoming historians, the facetious solution is to just ignore events of either even or odd numbered years. This would essentially halve the amount of data to go through and the amount of time to go through it, but it would be at the detriment of our understanding of all of the context of said events. As an example World War 2 started and ended on odd years, but some of the most tide-turning battles (Fall of France, most of Stalingrad, D-Day) happened on even years.
Although this format with small panels above and below a larger one has been seen before, there could be an extra joke this time, if it is seen as if there were originally five panels to the comic, but the second and fourth (the even ones) were removed.
[In a small panel top left, Cueball walks up to Megan who is sitting on an office chair holding a tablet showing a screen full of (to the reader) unreadable text.] Megan: I read this article in an old newspaper, and I can't stop thinking about it.
[Below is a large panel twice as wide as the first, and much longer. It contains the newspaper clip that Megan talks about. Three sections of the text is in normal black font, the rest is in gray font:] The public events of the last three months are of the class which will go into its permanent history. We have been living in an atmosphere of history which will be immortally preserved. Even the brief series of important dates to be collated for the use of the schoolboys of centuries hence will contain the day of the assassination, and the day of the death of President Garfield.
The intermediate events co-related, like the defeat of Roscoe Conkling, will be of great interest, but will scarcely be likely to stand prominently out from the page of history written in 1881. To us who have been the witnesses, so to speak, of the tragic incidents of the times, it seems entirely probable that future generations will eagerly scan every feature of the recent bereavement which the nation has suffered.
How accurately will future generations know the immense volume of grief and sorrow which has rolled over the land? Will those who come after us ever be able to understand the extent of our loss? Is there anything in the first century of our history—even the death of the great Lincoln—which can be used as a parallel?
Perhaps a careful reading of the daily papers of the present. period may give some future antiquarian a fine idea of the feelings of the nation during the past summer. But these journals are so large, so full of detail, that we imagine the coming American will never find time to read the record. He must depend on a brief statement, meagerly compiled by some dry and tedious historian.
—The Bloomington Daily Pantagraph September 30, th 1881
[The third and final panel is the same size as the first, below and to the right. It contains a zoom in on Cueball and Megan talking.] Cueball: Man. The past is so big . Megan: How do historians even cope? Cueball: I have no idea. Megan:  I honestly have enough trouble just with the present.


Turkish Delight

Explanation:
The Lion, the Witch and the Wardrobe is a fantasy novel by British novelist C. S. Lewis , the first published and best known of seven novels in The Chronicles of Narnia . In it, a group of four sibling children discover another world called Narnia. At the beginning of the story, the land is in a perpetual winter caused by the White Witch (the antagonist of the story). One of the children, Edmund Pevensie , is approached by the White Witch and offered Turkish delight , a type of confection, in exchange for leading the other children to her.  What the book says and what the movie leaves out is he doesn't know the sweets are enchanted by the White Witch to make the eater want them the more they eat them.  Not a full mind control, but more of a strong urge to get more.
Turkish delight is very different from typical confections found in the modern Western world and isn't very popular in the United States. The primary flavoring agent of Turkish Delights, rosewater, has a strong perfume-like taste and is generally considered an acquired taste for western palates. Randall , who has made comics about being unimpressed by food in the past, comments that he was very disappointed when he tried Turkish delight, especially after having read in the novel about how delicious the characters considered it. If he were in Edmund's shoes, he would not have been persuaded.
It is not uncommon for present-day Narnia fans to be disappointed when they try Turkish delight , as different as it is to modern confections. However, in the late Victorian era when Lewis grew up, Turkish delight was very popular in England .  Because it was nearly impossible for local confectioners to make properly, it had to be imported from Turkey, at great expense, making it a status symbol for the wealthy and a rare treat for those with less money. When Lewis wanted to come up with the perfect temptation for Edmund, he drew on his own childhood memories of a favorite rare and expensive treat--which would have been even harder to come by because of sugar rationing during World War II , when the story was set. It also serves to emphasize how powerful the White Witch is for her to be able to offer such an expensive and hard-to-obtain treat so easily.
Cinnabon (referenced in the title text) is a popular chain restaurant in the USA which serves mostly cinnamon buns covered in a thick, sugary glaze. The chain is not well known in Britain, but has recently opened a few restaurants , mainly in the London area. (A more common UK equivalent of the cinnamon bun is the Chelsea bun .) There are presumably no branches of Cinnabon in Narnia. [ citation needed ] Randall is saying that he finds cinnamon buns delicious, to the point where he would betray anyone for them. It should be noted that, in the books, it was Edmund who requested the Turkish Delight. Thus, had it been Randall instead of Edmund, he very well could have requested cinnabons.
[A person wearing a cap, a fur coat, and gloves sits in a sled handing over a plate with small cubic pieces on it to a small boy with dark hair standing beneath. The boy reaches one hand to the plate.] Person in the sled: Have some Turkish delight. If you betray your family, there's more where that came from.
[The boy tastes one piece.]
[The boy looks at that piece.]
[The boy looks up, to the direction where the gift came from, the piece still in his hands.] Boy: Wow. Boy: This is ... not great.
[Caption below:] The Narnia books gave me a really unrealistic impression of how good Turkish delight tastes.


Rickrolling Anniversary

Explanation:
Cueball tells Megan that by the release of this comic in April 2018 it is the 10th anniversary of the peak of rickrolling , and she is amazed that this has been so long ago. She then expresses a half-hearted happy anniversary wish, though it's not clear whether the anniversary she is congratulating is the phenomena itself having reached 10 years, or if she and Cueball met 10 years ago, coinciding with the height of the popularity of rickrolling, and this is reminding her to wish him a happy anniversary. After a beat panel Cueball concludes "We've known each other for so long", which is both a poetic affirmation of his friendship with Megan, and a line from the song " Never Gonna Give You Up ," the hit song by Rick Astley on which rickrolling is based.
The first reference to rickrolling in xkcd was in 351: Trolling from 2007, where Astley himself was Rickrolled by Black Hat . Black Hat then later uses Astley to show his girlfriend Danish how Rick rolls in 524: Party , a New Year party from the end of 2008.
Rickrolling had first started in 2007, but reached a peak in about April 2008 when, as an April fool's day prank, Youtube linked all its featured videos to Never Gonna Give You Up , and the New York Mets were Rickrolled by a public vote to choose a song for the 8th innings sing-song. This coincided with a sharp peak in searches for "Rick Astley" and related terms.
The title text refers to another old xkcd meme of giving snippets of information to the reader that make them feel old . Although comics such as 218: Nintendo Surgeon in 2007 refer to facts that could make you feel old, the first comic directly build around factoids to make one feel old in xkcd was 891: Movie Ages in April 2011. This was 7 years before the time of publishing. The Bush Kerry election was in November 2004, 6½ years before that comic, making the title text statement that the beginning of this meme is closer to that election that today. This is the way most of these make you feel old comics are built.
[Cueball and Megan are walking.] Cueball: This month marks ten years since the peak of the Rickrolling phenomenon.
[In a frame-less panel they keep walking.] Megan: Seriously? Megan: Wow. Happy anniversary, I guess.
[They keep walking silently, beat panel.]
[And they walk on.] Cueball: We've known each other for so long. Megan: We really have.


Evangelism

Explanation:
In this comic, Randall presents a line plot where causes are listed, in increasing order, by the intensity of the evangelism of their advocates. Evangelism , in Christianity , is the commitment to or act of publicly preaching of the Gospel with the intention of spreading the message and teachings of Jesus Christ. “Evangelism” is also defined as any zealous advocacy for a cause, religious or not.
The first punchline is that religious proselytizers are unexpectedly much less intense than advocates for such things as opening bananas from the other end—which is also the subject of the title text. The comic’s release date on April 18th, is likely correlated with this days assignment as the official “Banana Day” in the US. (However, at the time of release of this comic, this day was not mentioned on the Wikipedia list of food days in the US ).
As the graph moves from left to right, the issues at stake have less and less impact on the life of someone who “converts”, but the intensity and fervor of those spreading the cause increases. This is counterintuitive, which is the joke.
Below, each of the points on the chart, as well as the title text, is discussed.
Religious proselytizers
Religious proselytizers are the best known evangelists, and the term “evangelism” originally applied only to them. Christian faith remains roughly as popular as ever, but Christian evangelism has become less common and less accepted in the public sphere in recent decades, and often only practiced in specific venues. Randall contrasts them in this strip with four other groups which he finds to be more intense in their “evangelism”.
People who want the US to switch to metric
Unlike most of the world, the US uses US Customary units instead of metric units . The vast majority of the world population (and even some within the US) wish for the US to change, to the point that the US Congress already passed the Metric Conversion Act that U.S. President Gerald Ford signed into law on December 23, 1975. Though the US now uses SI units in many areas, especially professionally, most Americans deal more with US Customary units in their day-to-day lives.
Randall has made a conversion chart for helping US people with the confusing metric units: 526: Converting to Metric .
People who want the US to switch to metric but keep Fahrenheit
Pro-metric people who wish to keep the Fahrenheit scale rather than change to Celsius are ranked as slightly more evangelic. A common argument for keeping the Fahrenheit scale is due to 0°F equating to “really cold” and 100°F to “really hot” when talking about weather. Fahrenheit also has smaller degrees than Celsius, so temperatures can be cited more precisely, if necessary, without the need to include fractional degrees. This also gives Fahrenheit the advantage that “decades” of temperatures are more useful as in saying the weather is in the 40s or the 70s, for instance. Because the Celsius degree is larger, the range of temperatures within any decade is wider and saying the temperature is in the 10s may not be as useful as it is a wider range of temperatures, compared to Fahrenheit.
To many people, making the shift only partially may immediately seem very silly—and yet the people arguing for this are even more ardent than those that wish to shift entirely, perhaps precisely because of this immediate strangeness. Also, if someone is being an SI purist, supporting a full shift to SI units, one could argue they should be advocating a switch to Kelvin as the unit of thermodynamic temperature, even though Celsius has the status of an SI derived unit .
Fahrenheit versus Celsius has been the topic of 1643: Degrees and 1923: Felsius .
People who threw away their socks and bought all one kind
The reason to do such a thing would be that any two socks in your drawer will match, saving time since they don't need to be matched or rolled/folded. It also reduces the likelihood of ending up with an unmatched sock—or a whole stack of them—in your drawer. This is a problem that scientists have researched .
To ordinary people, it immediately seems quite aesthetically boring to always wear the same color of socks or other clothing. But it will be easier to find matching socks, so time is saved and there will be reduction in cost as no unmatched socks will have to be discarded. For those reasons, people that do this will recommend it quite ardently to all their friends, and, at least according to the comic, even more so than the pro-metric advocates.
Randall previously referenced this idea in the xkcd survey (see 1572: xkcd Survey ) from September 2015. It included this question:
People who open bananas from the other end
The most evangelic people Randall includes are the people who open bananas from the "other" end. Some people prefer to open bananas from the calyx end instead of the stem end. This thought is continued in the title text.
Title text
The title text describes a fictional argument that apparently somehow tore apart Europe between the two factions Other primates open them from the small end and But the little bit of banana at the small end is gross . It continues the most evangelic point in the chart about how bananas are supposed to be opened from the “right” end. It seems absurd that this could have actually happened, over such a trivial issue. However, major schisms in religion, such as that between Catholicism and Protestantism (which did, in fact, split Europe) may seem similarly trivial to the non-religious.
The supposed argument stems [ pun intended ] from a disagreement between those that find it easier to open a banana from the bottom and those that find the small bit at the base of a banana unappetizing.
Though primates do not eat bananas in the wild , in captivity, some have been observed to open bananas from the bottom end away from the stem, as one of the two factions refers to. Less force is required to open a banana at the bottom than at the stem, causing less bruising of the fruit and generally making it easier to open. However, if not done carefully, this can result in the fruit getting squished and making a mess on the person’s fingers. Opening bananas from the stem end appears to be the predominant habit of most banana-eating humans (in Randall’s sample). One explanation is that using the stem as a lever makes for greater ease of opening and thus less damage in practice.  (Bananas grow with the stem at the bottom ).
The entire "correct banana end" discussion could be a reference to the wars between the Blefuscudians, who opened their eggs at the big end, and the Lilliputians, who broke their eggs at the small end, as told in Jonathan Swift’s epic novel Gulliver’s Travels . This in turn is the origin of the terms "Little Endian" and "Big Endian" which were much debated in circa 1980's computer architectures - which may also have been on Randall's mind.
Randall’s thoughts on the problems with opening bananas could also explain why this fruit, which many find very easy to peel and consume, is listed in the middle of the easy/difficult scale in the 388: Fuck Grapefruit chart.
[A chart is shown with a line drawn from left to right with five markers on it. Each marker has a line going to it from a labeled below the main line. Above this there is a title and right below that a label above an arrow pointing to the right.] People by intensity of evangelism More intense
Religious proselytizers People who want the US to switch to metric People who want the US to switch to metric but keep Fahrenheit People who threw away their socks and bought all one kind People who open bananas from the other end


Clutter

Explanation:
As the graph shows, the amount of junk sitting around Randall 's house is on an ever-increasing trend. Thus, it will continue to pile up and cause problems.
Randall cleans up sometimes, thinking that he is returning to the same baseline amount of stuff each time, but it is not actually effective enough to keep up with the cluttering trend, and hence his worry.
The four places on the graph where the amount of stuff decreases reference common times when people clean up and get rid of junk or excess stuff.  This includes:
Although not mentioned in the quotes, it is also common in the United States to clean up and donate items (for instance to Goodwill) on December 31st, right before the New Year, to gain the charitable donation benefit on their taxes for that year.
The title text refers to the book The Life-Changing Magic of Tidying Up: The Japanese Art of Decluttering and Organizing by Marie Kondo . The main concept of the book is that one should gather all belongings and only retain items that "spark joy". Ironically, the thought of reading the book didn't spark joy for Randall so he decided to donate it.  Thus, one of the few things that he did get rid of was something that if he had kept and put into practice could have helped him actually reduce his clutter.
[There is a panel containing a line graph. The x- and y-axes are labeled "time" and "amount of stuff in my house" respectively.] [The y-value generally increases straight-line as x increases. There are a few labeled exceptions where the y-value decreases slightly but instantly increases again. From left to right:] "I need to clean up." "I've really let junk build up. Feels good to clear it out." "I hate moving, but at least it's a chance to finally get rid of all this excess stuff." "Ah, spring cleaning!"
[Caption below the panel:] I'm starting to worry about my strategy for dealing with clutter.


Misinterpretation

Explanation:
Cueball is complaining that people are mad at him again because of a misinterpretation of his statements. This is referenced by the comic's title. He complains that since (he believes) he is being perfectly clear, it cannot be his fault that everyone misinterprets him. The off-screen voice sarcastically agrees that communication is an activity that only involves one person; in fact, of course, it famously involves at least two .
Cueball speaks as though his communications are complete and perfect once he has finished making them. The reality is that communication can't be considered complete until the message has also been received and understood. Cueball is failing to take into account the need for partnership between sender and receiver, and doesn't realise that the problem may well be in the way he carries out his side of the transaction rather than in the way everybody else is carrying out theirs.
In the title text, Cueball then answers that he cannot possibly account for the many possible interpretations which the message, potentially reaching the whole world, could acquire. This is an example of the Nirvana fallacy . Cueball's idealized solution is to consider how every person on Earth would interpret the message, so Cueball rejects doing anything less as insufficient; however, actually figuring out how every person on Earth would interpret the message is unfeasible, so Cueball doesn't do that either. The reply comes once again sarcastically, deriding his point and saying that a middle ground between taking up such an effort and entirely avoiding it must be reached.
This avoidance is phrased using a simile as “covering your eyes and ears and yelling logically correct statements into the void”, implying that no one would understand the logical sentences (thus the void), and would instead read them more naturally – and also that ignoring the appalled reaction of listeners to their own interpretation of the sentences is similar to covering your eyes and ears. This action makes communication more difficult through the popular [ citation needed ] means of speech, text and sign language. If the hands are occupied with covering either part, then Braille communication is also impossible. Therefore, the action of “covering your eyes and ears” is a metaphor for deliberately making it more difficult to communicate with oneself. The simile might also mean that Cueball subconsciously rejects criticism as it would hurt his ego.
It is clear that Cueball is acting as a straw man to further Randall's point, and the off-panel character is portrayed as the (sarcastic) voice of reason.
Randall returns to a recurring theme in his comics, regarding, in contexts of communication, the responsibility of the speaker for how they are interpreted. Having gradually gotten less subtle, this theme is now laid bare, there being no joke other than the sarcasm. What follows is a chronological history of this theme.
This theme is part of the larger category of comics about social interactions .
[Cueball is sitting in an office chair at a desk in front of a laptop with his hands raised above the keyboard. An off-panel person replies to his remarks.] Cueball: Ugh, people are mad at me again because they don't read carefully. Cueball: I'm being perfectly clear. It's not my fault if everyone misinterprets what I say. Off-panel person: Wow, sounds like you're great at communicating, an activity that famously involves just one person.