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February 2009  
  
Hacker News was two years old last week. Initially it was supposed to be a
side project—an application to sharpen Arc on, and a place for current and
future Y Combinator founders to exchange news. It's grown bigger and taken up
more time than I expected, but I don't regret that because I've learned so
much from working on it.  
  
**Growth**  
  
When we launched in February 2007, weekday traffic was around 1600 daily
uniques. It's since grown to around 22,000. This growth rate is a bit higher
than I'd like. I'd like the site to grow, since a site that isn't growing at
least slowly is probably dead. But I wouldn't want it to grow as large as Digg
or Reddit—mainly because that would dilute the character of the site, but also
because I don't want to spend all my time dealing with scaling.  
  
I already have problems enough with that. Remember, the original motivation
for HN was to test a new programming language, and moreover one that's focused
on experimenting with language design, not performance. Every time the site
gets slow, I fortify myself by recalling McIlroy and Bentley's famous quote

> The key to performance is elegance, not battalions of special cases.

and look for the bottleneck I can remove with least code. So far I've been
able to keep up, in the sense that performance has remained consistently
mediocre despite 14x growth. I don't know what I'll do next, but I'll probably
think of something.  
  
This is my attitude to the site generally. Hacker News is an experiment, and
an experiment in a very young field. Sites of this type are only a few years
old. Internet conversation generally is only a few decades old. So we've
probably only discovered a fraction of what we eventually will.  
  
That's why I'm so optimistic about HN. When a technology is this young, the
existing solutions are usually terrible; which means it must be possible to do
much better; which means many problems that seem insoluble aren't. Including,
I hope, the problem that has afflicted so many previous communities: being
ruined by growth.  
  
**Dilution**  
  
Users have worried about that since the site was a few months old. So far
these alarms have been false, but they may not always be. Dilution is a hard
problem. But probably soluble; it doesn't mean much that open conversations
have "always" been destroyed by growth when "always" equals 20 instances.  
  
But it's important to remember we're trying to solve a new problem, because
that means we're going to have to try new things, most of which probably won't
work. A couple weeks ago I tried displaying the names of users with the
highest average comment scores in orange.  That was a mistake. Suddenly a
culture that had been more or less united was divided into haves and have-
nots. I didn't realize how united the culture had been till I saw it divided.
It was painful to watch.   
  
So orange usernames won't be back. (Sorry about that.) But there will be other
equally broken-seeming ideas in the future, and the ones that turn out to work
will probably seem just as broken as those that don't.  
  
Probably the most important thing I've learned about dilution is that it's
measured more in behavior than users. It's bad behavior you want to keep out
more than bad people. User behavior turns out to be surprisingly malleable. If
people are expected to behave well, they tend to; and vice versa.  
  
Though of course forbidding bad behavior does tend to keep away bad people,
because they feel uncomfortably constrained in a place where they have to
behave well. But this way of keeping them out is gentler and probably also
more effective than overt barriers.  
  
It's pretty clear now that the broken windows theory applies to community
sites as well. The theory is that minor forms of bad behavior encourage worse
ones: that a neighborhood with lots of graffiti and broken windows becomes one
where robberies occur. I was living in New York when Giuliani introduced the
reforms that made the broken windows theory famous, and the transformation was
miraculous. And I was a Reddit user when the opposite happened there, and the
transformation was equally dramatic.  
  
I'm not criticizing Steve and Alexis. What happened to Reddit didn't happen
out of neglect. From the start they had a policy of censoring nothing except
spam. Plus Reddit had different goals from Hacker News. Reddit was a startup,
not a side project; its goal was to grow as fast as possible. Combine rapid
growth and zero censorship, and the result is a free for all. But I don't
think they'd do much differently if they were doing it again. Measured by
traffic, Reddit is much more successful than Hacker News.  
  
But what happened to Reddit won't inevitably happen to HN. There are several
local maxima. There can be places that are free for alls and places that are
more thoughtful, just as there are in the real world; and people will behave
differently depending on which they're in, just as they do in the real world.  
  
I've observed this in the wild. I've seen people cross-posting on Reddit and
Hacker News who actually took the trouble to write two versions, a flame for
Reddit and a more subdued version for HN.  
  
**Submissions**  
  
There are two major types of problems a site like Hacker News needs to avoid:
bad stories and bad comments. So far the danger of bad stories seems smaller.
The stories on the frontpage now are still roughly the ones that would have
been there when HN started.  
  
I once thought I'd have to weight votes to keep crap off the frontpage, but I
haven't had to yet. I wouldn't have predicted the frontpage would hold up so
well, and I'm not sure why it has. Perhaps only the more thoughtful users care
enough to submit and upvote links, so the marginal cost of one random new user
approaches zero. Or perhaps the frontpage protects itself, by advertising what
type of submission is expected.  
  
The most dangerous thing for the frontpage is stuff that's too easy to upvote.
If someone proves a new theorem, it takes some work by the reader to decide
whether or not to upvote it. An amusing cartoon takes less. A rant with a
rallying cry as the title takes zero, because people vote it up without even
reading it.  
  
Hence what I call the Fluff Principle: on a user-voted news site, the links
that are easiest to judge will take over unless you take specific measures to
prevent it.  
  
Hacker News has two kinds of protections against fluff. The most common types
of fluff links are banned as off-topic. Pictures of kittens, political
diatribes, and so on are explicitly banned. This keeps out most fluff, but not
all of it. Some links are both fluff, in the sense of being very short, and
also on topic.  
  
There's no single solution to that. If a link is just an empty rant, editors
will sometimes kill it even if it's on topic in the sense of being about
hacking, because it's not on topic by the real standard, which is to engage
one's intellectual curiosity. If the posts on a site are characteristically of
this type I sometimes ban it, which means new stuff at that url is auto-
killed. If a post has a linkbait title, editors sometimes rephrase it to be
more matter-of-fact. This is especially necessary with links whose titles are
rallying cries, because otherwise they become implicit "vote up if you believe
such-and-such" posts, which are the most extreme form of fluff.  
  
The techniques for dealing with links have to evolve, because the links do.
The existence of aggregators has already affected what they aggregate. Writers
now deliberately write things to draw traffic from aggregators—sometimes even
specific ones. (No, the irony of this statement is not lost on me.) Then there
are the more sinister mutations, like linkjacking—posting a paraphrase of
someone else's article and submitting that instead of the original. These can
get a lot of upvotes, because a lot of what's good in an article often
survives; indeed, the closer the paraphrase is to plagiarism, the more
survives.   
  
I think it's important that a site that kills submissions provide a way for
users to see what got killed if they want to. That keeps editors honest, and
just as importantly, makes users confident they'd know if the editors stopped
being honest. HN users can do this by flipping a switch called showdead in
their profile.   
  
**Comments**  
  
Bad comments seem to be a harder problem than bad submissions. While the
quality of links on the frontpage of HN hasn't changed much, the quality of
the median comment may have decreased somewhat.  
  
There are two main kinds of badness in comments: meanness and stupidity. There
is a lot of overlap between the two—mean comments are disproportionately
likely also to be dumb—but the strategies for dealing with them are different.
Meanness is easier to control. You can have rules saying one shouldn't be
mean, and if you enforce them it seems possible to keep a lid on meanness.  
  
Keeping a lid on stupidity is harder, perhaps because stupidity is not so
easily distinguishable. Mean people are more likely to know they're being mean
than stupid people are to know they're being stupid.  
  
The most dangerous form of stupid comment is not the long but mistaken
argument, but the dumb joke. Long but mistaken arguments are actually quite
rare. There is a strong correlation between comment quality and length; if you
wanted to compare the quality of comments on community sites, average length
would be a good predictor. Probably the cause is human nature rather than
anything specific to comment threads. Probably it's simply that stupidity more
often takes the form of having few ideas than wrong ones.  
  
Whatever the cause, stupid comments tend to be short. And since it's hard to
write a short comment that's distinguished for the amount of information it
conveys, people try to distinguish them instead by being funny. The most
tempting format for stupid comments is the supposedly witty put-down, probably
because put-downs are the easiest form of humor.  So one advantage of
forbidding meanness is that it also cuts down on these.  
  
Bad comments are like kudzu: they take over rapidly. Comments have much more
effect on new comments than submissions have on new submissions. If someone
submits a lame article, the other submissions don't all become lame. But if
someone posts a stupid comment on a thread, that sets the tone for the region
around it. People reply to dumb jokes with dumb jokes.  
  
Maybe the solution is to add a delay before people can respond to a comment,
and make the length of the delay inversely proportional to some prediction of
its quality. Then dumb threads would grow slower.   
  
**People**  
  
I notice most of the techniques I've described are conservative: they're aimed
at preserving the character of the site rather than enhancing it. I don't
think that's a bias of mine. It's due to the shape of the problem. Hacker News
had the good fortune to start out good, so in this case it's literally a
matter of preservation. But I think this principle would also apply to sites
with different origins.  
  
The good things in a community site come from people more than technology;
it's mainly in the prevention of bad things that technology comes into play.
Technology certainly can enhance discussion. Nested comments do, for example.
But I'd rather use a site with primitive features and smart, nice users than a
more advanced one whose users were idiots or trolls.  
  
So the most important thing a community site can do is attract the kind of
people it wants. A site trying to be as big as possible wants to attract
everyone. But a site aiming at a particular subset of users has to attract
just those—and just as importantly, repel everyone else. I've made a conscious
effort to do this on HN. The graphic design is as plain as possible, and the
site rules discourage dramatic link titles. The goal is that the only thing to
interest someone arriving at HN for the first time should be the ideas
expressed there.  
  
The downside of tuning a site to attract certain people is that, to those
people, it can be too attractive. I'm all too aware how addictive Hacker News
can be. For me, as for many users, it's a kind of virtual town square. When I
want to take a break from working, I walk into the square, just as I might
into Harvard Square or University Ave in the physical world.  But an online
square is more dangerous than a physical one. If I spent half the day
loitering on University Ave, I'd notice. I have to walk a mile to get there,
and sitting in a cafe feels different from working. But visiting an online
forum takes just a click, and feels superficially very much like working. You
may be wasting your time, but you're not idle. Someone is wrong on the
Internet, and you're fixing the problem.  
  
Hacker News is definitely useful. I've learned a lot from things I've read on
HN. I've written several essays that began as comments there. So I wouldn't
want the site to go away. But I would like to be sure it's not a net drag on
productivity. What a disaster that would be, to attract thousands of smart
people to a site that caused them to waste lots of time. I wish I could be
100% sure that's not a description of HN.  
  
I feel like the addictiveness of games and social applications is still a
mostly unsolved problem. The situation now is like it was with crack in the
1980s: we've invented terribly addictive new things, and we haven't yet
evolved ways to protect ourselves from them. We will eventually, and that's
one of the problems I hope to focus on next.  
  
  
  
  
  
**