skysight-inc/HackerNews huggingface dataset:
I once heard of a system for representing threaded comments in a relational database, wherein the ID of each comment was a slash-separated list of its ancestors, e.g.:

1 Initial comment

1/1 Re: Initial comment

1/2 Re: Initial comment

1/2/1 Re: Re: Initial comment

1/2/2 ...

These sorts of IDs have the wonderful property that you can efficiently select any subtree using a LIKE query, e.g. "SELECT * FROM comments WHERE path LIKE '1/%'". These queries are efficient because they use string btree indexes. And the results may even be sorted the right way, provided you have monotonically increasing IDs within each level.

I think I read about this technique being used on Slashdot a few years ago, but I can't remember the name or find any reference. Still, it seems like a way to achieve the same benefits that the OP cites for comments with PostgreSQL's ltree support on any database with reasonable string indexing.

Anyone know the name of that technique?
What's wrong with a feel-good distraction? Instead of implementing "Hello World" in 120 languages, why not tinker with papercup designs?
About 75% of our signups come from the homepage CTA so I only bothered to test that one. Also I wasn't sure if A/Bingo let you run the same test in multiple places.

I'm working on replacing the green footer call to actions today with the get started now.
HTML map tag
any...day...now.

Like tomorrow? http://www.quitfacebookday.com/
http://www.bingocardcreator.com/abingo , apparently.

The brief version is that you cookie each visitor with a random unique identifier. Each identifier maps to one of the versions under testing in a durable fashion. The first time you see an identifier for a particular test, you increment the participant count for that appropriate version. When a conversion -- here a signup -- happens, you look at the identifier, check what version they saw, and increment the conversion counter. From then it is just a math problem. So when you see a conversion rate like 24%, that implies that 24% of people who viewed a page the test was active for signed up prior to becoming lost to the system. (By, for example, leaving forever, clearing cookies, etc.)

Although one could theoretically exclude folks who log in later from the participant count, I think that is a poor use of your time for most people. Existing site users will be split across all alternatives evenly, so their failure to sign up for the site affects all alternatives easily. Since A/B testing doesn't really care about the exact value of the conversion rates and focuses on the differences between them, that comes out in the wash. (Plus, for many services, first time visitors swamp existing users of the service, so even if you were worried about distortion it would be minimal.)
The conversion rate I posted at the top of the article is for new visitors to my site (not including returning).

The metric we used in the a/b tests was signups and the participants are anyone who lands on the homepage (new or returning).
Why not hold only the particular neurons responsible for a crime accountable?
His original point still stands. If not BP, then it would've been another company. As consumers we demand low oil prices, the oil companies cut corners to meet that demand and it has consequences.
Train networks are public – not private – projects in Europe or they were, at least, at the time they were built. I don’t know about the US but that’s why I think trains might not be such a good example.
I believe you are referring to Materialized Path:

http://www.mjcblog.net/2009/03/full-tree-selects-via-materia...
The author is Chris Bishop... who wrote one of the "essential" machine learning books :

http://www.amazon.com/Pattern-Recognition-Learning-Informati...
Threaded comments are surprisingly difficult to model in a relational database. I spent about a month on the problem when I rolled my own threaded comment system for newsley. Relational Databases really don't lend themselves to easily modeling tree structures.

If you're interseted in doing something like this, I'd highly recommend this book: http://www.amazon.com/Hierarchies-Smarties-Kaufmann-Manageme...

He has two really good chapters that specifically building a comment system. It takes a bit of work, and you end up pre-computing the comment system on INSERT's instead of SELECT's. But, you can build a comment system that pulls your entire comment tree in order using a single SELECT ... FROM COMMENTS ... ORDER BY comment.node_left;
It might not be a big deal but the difference isn't significant at 95% confidence level. It is significant at 90% confidence level but I personally prefer to shoot for >95% and ideally 99% confidence level.
I've read this over and over again, and I can't tell if you're agreeing or disagreeing with me!

Defocus spreads a point of light over more than one point in the image... as does the "antialiasing filter."
Nice:

Also notice that setting negative values for a yields integrals.
For eight years the United States had a government that was bought, paid for and owned by the oil industry. And the oil industry thought that this was a very good thing. Then the law of unintended consequences kicks in and the result will be that things will be much more difficult for the oil industry, or at least offshore drilling, for the foreseeable future.
Right on. I don't recall hearing that particular name, but it's certainly the same idea.
To keep with the anecdotes - I have friends who when they meet up normally pull their laptops out for some farmville (and to plan how to get the next level/cow/whatever). It does happen.

But great observation on the iPhone games thing - one of the discussions at our extended family dinner every couple of weeks is the new iPhone/iTouch apps we have.. "Hey check this out" is really effective marketing (as of course it is in every industry)
I think that a problem with this idea is that the "expandable yet sturdy bag" would have to be able to withstand great pressure, not just of the oil itself but to survive a mile underneath the ocean.
Interesting; his results pretty accurately follow the startup activity in cities. San Francisco, New York, Boston. The startup activity difference is about the square of the spread in his graph, though.
I Prefer Safari to Content Apps On The iPad
It should be called "Materialized Path".

See: http://troels.arvin.dk/db/rdbms/links/#hierarchical
I'm tired of the straw man arguments used here. Regardless of if you agree with the gist of his posts, (and I do), no one is saying one download is one lost sale, but to say that no downloads are lost sales is disingenuous. You can say that they are sales you don't care about if you want, but there are definitely lost sales.

Secondly, you don't have to interview every pirate in order to find out. If that were true, it would be impossible to predict elections without... taking everyone's vote. I have a feeling Nate Silver would have a few words for this guy.
8 years? I think you dropped a zero, or are woefully ignorant of the history of this great nation.
-TCP/IP scripting language - Both ruby and python support working with low-level socket objects, so that's probably a good place to start. If you're looking for something lower-level, scapy ( http://www.secdev.org/projects/scapy/ - python) might be a worth a look.

-Binary watermarker - You might look into SELinux to see if it will do what you want.

-Subversion plug-in - A pre-commit hook that runs pylint/reek against your code and spits back FAILED is pretty cool.

-Website scanner - There's a list of a few existing scanners on google's webmaster forum (http://www.google.com/support/forum/p/Webmasters/thread?tid=... ). And there is also an obvious route to monetization.
Jewish Failure?
My strong bias is towards getting the technical background.

If you have that, partnering with more technical people is a lot more likely to work, otherwise the only possible posture that works is blind trust, which most people aren't capable of.

However this is coming from the son of a businessman who started reading his Wall Street Journal in 3rd grade, so I've found partnering with business people to be easy (amusingly, in many of the startups I've worked for I've helped the point man procuring office space, since unless you have a background in that area you e.g. have no idea how slow the real estate clock cycle is).

To finish, when you think of the historical hardware and software long term superstars many if not most were founded and lead by at least one person with serious technical chops, perhaps even uber-salesman Larry Ellison of Oracle.

Obvious examples are Bill Gates, Jeff Bezos of Amazon, the founders of Google and the Chairman/CEO they picked, Ken Olsen of DEC, H&P of HP and I'm sure I'm forgetting many others.

Tom Watson, Jr., who saved IBM with his massively successful push into computers, is the most famous exception to this pattern ... but seeing that he grew up in the predecessor punched card industry and undoubtedly absorbed a lot of technical stuff including most especially attitudes he's got to be a special case.

As you probably know, the list of technical companies ruined by non-techie leaders is nearly infinite, but it's balanced at least in part by techies not getting the business side of things. Can any of you think of major counterexamples of complete non-techies who massively succeeded over a long term, including retaining their initial key technical people?

Steve Jobs is the only one I can think of off the top of my head (and he fails the retention test, e.g. he burned out the Macintosh development team, didn't he?) but he clearly has unique relevant design talents that make him a special case.
At the risk of sounding flip, not supporting punycode sounds like a feature. Getting internationalization right is clearly important, but punycode as a means of doing so? It's one of the many things that make me weep for my industry.

In fact, I often wonder if punycode is a prank that got out of hand.

UTF-8, on the other hand, would have been excellent for this purpose.
Ok, so you seriously don't think temporarily banning deepwater drilling is reasonable, given the circumstances?
This article is so sickeningly off-base that I don't even want to talk about how wrong it is.
Apple Tries To Steer Labels Away From Amazon's Daily Deal
Errr, which emergency shut off are you referring to?

An acoustic signaler? The utility of that is highly unclear, the BOP after all has a deadman system to engage if it loses its connection to the rig. Everything I've heard indicates the BOP failed in its primary function, for reasons we won't be sure of until it can be removed and examined (it might be something as simple as it not being able to shear through pipe couplings).
The "signup for free" part had me wondering. "Sign up" is the verb, where "signup" is a noun. I wonder if the benefit was just in eliminating the misused word. Most other A/B tests I've seen favor the phrase with "free" in it.

It's similar to the "login" vs. "log in" discussion, but I think it's a bit more clear cut with "sign up."
It might be reasonable - we aren't experts so it's impossible to know if this incident is part of a wider risk. But this big thing about banning it till 2011 is political posturing. Suspend things, let the experts review and decide on the safety, then make a decision.
Exactly - and anyone on HN should be easily able to use the Friend Lists stuff within facebook. Chat Status, Privacy settings and just the ability to filter down into smaller subsets.. So while I am 'friends' with 320 people.. I see almost everything from the people I'm truly close with, while occasionally dipping into the greater stream from of other acquaintances. While facebook could do some better outreach on some of this stuff (my Dad was overjoyed to find out last week you can block applications -- no more farmville in the news feed), we on HN should be able to use it properly. There's plenty of reasons to complain about fb, but cheapening friendship is not one of them.. it is completely about how you use the tool.

Also - (at least among my general circle - mid 20's, Australia, almost completely non-tech) - Serious personal conversation is now almost predominately facebook. Almost every party (excluding weddings/engagements) is a FB event (with maybe SMS invites). IM = Facebook chat. And email = Facebook PM.
Both A/Bingo and Vanity split participants in essentially the same fashion: each new participant is assigned totally randomly. (Not only is it the same effect, the algorithm we use for it is practically identical, too.)

This tends to produce a phenomenon well-known to coin flippers: the more coins you flip, the closer the percentage of heads and tails will converge to 50/50 and the farther your counts of heads and tails will diverge from each other.
Or use EMACS and its kill ring and multi-level undo (although stock GNU EMACS doesn't put single character deletes into the kill ring).
Cause or effect?

The first thing I thought when I saw the graph was that the cities with the most college graduates per capita were also the most expensive. Could it be that college graduates are the only ones who have earned enough to afford these places?

Also the idea that (CollegeEducation = SmartPeople) is really played out. Many of the smartest people I know have achieved great things in spite of or instead of college. Finishing college is as much a matter of determination as "smartness", whatever that means.
Poll: Do you want your employer to be successful?
They started drilling the relief well in early May - http://online.wsj.com/article/SB4000142405274870434260457522... .

I can't find a time frame on how long the relief well would take, I suspect a while. (It took 9 months for the first well to come online in the Ixtoc 1 spill, and even then it took another 3 months for the flow to subside). The political suicide comes from human nature needing to see something being done.
"Uh, so we have a fix in place. Oh yeah, it's gonna take a year to work."
"So what do we do now?"
"Wait."
I had the very good fortune of having Peter Norvig as a technical editor of one of my books. Unfortunately there were a lot of problems with my book that needed fixed and I appreciated the precise way he told me what he didn't like. He is certainly one of the best computer scientists on the planet, and also a very nice guy.
It's far to early to pin blame like that. I will be the first one to beat down the door when it is time, but let's not get too hasty with all this.

(fwiw I think in terms of cut out systems they were reasonably installed - that the bop failed could be an act of god or negligence: we have no idea yet. The possible negligence, and cause, elsewhere is another matter)
This always strikes me as a sanitation nightmare, when I see staff heading over the sink to rinse out... who knows what. Most cups are probably fairly clean, but I imagine a portion of them being a problem to one degree or another.

After staff rinses the cup, do they wash their hands? How careful are or do they need to be in avoiding cross contamination when they handle the equipment to fill the cup?

Then again, they are already handling money from customers, so I don't know whether it really makes much difference. But while I appreciate the sentiment of bring your own, I always wonder how much staff time, cleanliness, water (hot water?), etc. it is costing. (I don't know -- just wonder.)
I really didn't pay a ton of attention to kuro5hin... but what I did read there wasn't what I would call right-wing. Essays like one that was abused to create the recent Wikipedia pedophile scandal were much closer to what I remember.
Are you talking about PLA and the like? It's pretty much a biodegradable/compostable plastic made from corn starch or sugarcane. I've seen utensils made from it in some cafeterias. But they can make lots of things with it, here they make coffee cups: http://www.cagreen.ca/Hot%20Cups-0
He is talking about the smart phone market. You may add the iPad (tablets) to that.
Evernote CEO calls BS on “the best product doesn’t always win” (video)
it's more that level of educational achievement correlates pretty well with IQ.
Note that my answer will be hugely biased, but then again so will everyone else's. ;)

Nonetheless, I'd say to go for the MSCS (or similar). You're looking for the networking potential of going back to school, and you want to start a start-up. In a technical master's program, you'll be around exactly the sort of people you need to meet for this to happen. In an MBA program, you'd network with a bunch of other business guys, many of whom wouldn't be interested in start-ups at all.

You'll obviously also gain a lot of truly valuable technical skills. You might not be able to single-handedly carry the technical side of a start-up by the end, but you'll definitely be able to make meaningful contributions and decisions about the technology. This helps your future partners as well, since they know you can contribute to the tech while working the business side.

If you're worried about missing out on the education side of the MBA, don't be. I think you could get a better version of an MBA education by just buying a pile of books [1] and starting a company. You'll learn everything you need about business along the way. And, as for the networking part of an MBA, you'll get way more interesting conversations out of "I'm running a start-up" vs. "I'm working on my business degree."

[1] Possibly a topic for another thread, but here's an example of such a reading list: http://personalmba.com/best-business-books/
I figured as much. It's likely that I noticed it because in the environment I use Vanity theres about much more traffic than on carelogger so the numbers even out much more quickly.
I wonder if the makers of the betacup challenge were aware of that - I suppose not...
Ask HN: Who's hiring?
I've recently started my job search, and it appears it's been about a month since the last "who's hiring" post. I think it's time for a fresh one.

Please include the location if you need employees to work on-site.

For reference, here's the last "who's hiring" post I could find that had any traction: http://news.ycombinator.com/item?id=1308582
I would like to see normalized versions of these nuumbers, eg density-of-smart-people / population-density. Of course new york city is going to be more dense than oklahoma city, but TFA tells us nothing about the relative densities of smart people.
From a "60 Minutes" interview with a surviving on-site worker, we have pretty strong allegations that a mistake followed upon by willful negligence destroyed the effectiveness of the cutoff device and then chose to ignore same.

There is a plausible argument that this aided the decision to proceed with subsequent mistakes. For example, if the device was compromised as described, pressure readings would be incorrect.

If there is no criminal investigation, I will consider the governments involved effectively (entirely) compromised.
If you've reached a point where this is even a question, it's time for you to get out and find something else to do with your time.

Employment is not chattel slavery, if you are dissatisfied with your workplace to the point where you want the organization to fail; then either fix the issues that are making you feel that way or get out.
The underlying link was originally submitted here: http://news.ycombinator.com/item?id=1380721

I don't think this blog post adds much, honestly, but this submission seems to have mysteriously caught fire while the other thread languished.
Out of curiosity, why?

To me, there is a difference between theoretical significance and practical significance. A 90% likelihood that the second version is actually better than the first version is enough for me to switch.

What is the downside of switching? About 10% of the time you'll be making a change that is no better than the old version. Unless you REALLY love green buttons, I think it's worth the risk. :)
It's not entirely clear that BP didn't screw up beyond the normal pale, but he is right that if you live in a society run on fossil fuels, this shit is going to happen.

The problem is, that people who are trying to move to a society not run on fossil fuels have to pay the exact same consequences as the people chanting 'drill, baby, drill!'
If it turns out BP did everything right and it was just the one in a million accident I will agree, but so far it looks like they took a lot of extra risks and effectively made the short straw.
Agree. This is a particularly frustrating/disgusting aspect. So few people (I'm speaking particularly of those in the U.S.) apparently consider their own role in this. The country's voracious appetite for "cheap" energy. Continued avoidance of investment in and implementation of efficiency measures. Repeatedly electing officials who neuter effective regulation.

Don't forget who put BP where they are.
His point was that downloads also result in sales - and that there is no evidence that more sales are lost than are gained.
I believe that copyright as security for business models idea is contrary to the survival of entrepreneurs in the free market.

I may not be as successful businessman as you, but my experience, knowledge of other people's experience, a knowledge of economic history concerning copyright as well empirical evidence, has led me to conclude that the notion for and support of copyright is dangerous thinking to an entrepreneur.

Take it as you like, but that's my version of the truth, a truth that has recently been vindicated by a game developer I really admired, though I knew it has proven to me countless time before.

Hopefully, in the near future, I am going to see if my business experiment bare fruits to the truth that I thought I know.

If I am right, I might be the video game industry's most dangerous businessman. While everyone has mired themselves in the sand for their moral reflex against the internet piracy, I have the true map of reality.

So why am I telling you? Well, I am actually torn between the value of telling people the truth and the good news, but I have every interest not to educate my competitors.

Perhaps, telling people doesn't really "educate" people because they stick their head in the sand. So my telling actually serve my both greed and help values.

Yeah, I am probably a snotty 19 years old who don't know better because he doesn't having much of an entrepreneurial experience. Better not take advice from a 19 years old who only want free stuff, right?
Yeh I saw that too; it certainly doesn't look good.

I think we will see a criminal investgation - especially as this is a new gvernment, and the public are definitely asking for it to happen. I'll be interested to see the conclusion - my prediction? A mixture of accidents, mistakes and negligence which combined into a "fluke" accident. Heads will role :-) (which is another reason to take it slowly/calmly - it will be much easier for any culprits to pin blame in the current confusion)
Would my money be better spent on a MBA or MSCS?

Neither.

1. Find someone who needs something.

2. Start building it.

3. Trust that when you need to learn something, you will.

The education you will receive this way will be way better than any formal education for multiple reasons. First, you will automatically triage your lessons; you will learn what you need, not what someone else (who probably doesn't know) thinks you need. Second, almost all the "data" you will need in this education is easily available and free. Third, for the education you need from other people, you will begin building a network you'll need anyway. And finally, this is exactly what you'll have to do whether or not you get any more formal education, so just skip the unnecessary step and get on with on. From your own self description, you already have way more formal education than you need.

This may not seem intuitive, but believe me, this is the way things get done in the real world of software development. At this point, the creme rises to the challenge regardless of education. Save your money for living expenses and start-up expenses. You'll probably need it. Best wishes!