Like the Internet itself, 404 pages are kind of in the high school of their existence. Just hear me out. The crusty old 404s of our youth are slowly being replaced by unique error messages custom-built by each website. They're not just about telling you something's wrong anymore. Interacting with a website has become a much more holistic experience. They've grown up past the basic functionality of an error page into something with personality and a sense of identity. And it's time to recognize the accomplishment of coming of age.
Like high school seniors, some are more mature than others.
Most Profane goes to South Park:
On the other hand, facebook and Yahoo! are customized but pretty straightforward or even boring. I guess when even /404 links to something, and you're assured of a billion users, a cute error page is not your top priority.
Most Likely to Succeed goes to Facebook. Because, like, they already have:
And then there are the un-cute error pages that make you worry. The idea that Google could not find something is a little odd, if you think about it too much (or reassuring, depending on how paranoid you are).
And so, Most Understated goes to Google:
Some have developed maybe a little too much personality, to make up for shortcomings. The Tumbeasts of Tumblr are, some misguided people might argue, overkill. But, it adds entertainment value to effectively diffuse the disgruntledness at Tumblr crashing all the time.
Most Popular goes to Tumblr, hands down:
[Tumblr appears to have changed their error page, so this is stolen from google images]
Some are truly unique, and deliver just as much value as the page you were looking for. I would definitely try to get to an error page if I knew it was always going to be this awesome.
Most Entertaining goes to Home Star Runner [click on the image for the full effect]:
Many people come of age philosophically in high school, and apparently some 404 pages have, too.
And then there are those who just refuse to be adults in the way their teachers and principals want them too, and rub it in your face all the time, but you can't really hate them for it, because secretly you want to be them, or at least be near them:
Most Unapologetically Badass goes to the Rolling Stones:
Some might say that these funny error pages are just cute gimmicks. But is that all it is? A creative page not found adds to the overall impression of the site, of the company. In the past, you'd pull back the curtain to find the wizard running the machine and discover that actually, this website isn't as intuitive and simple as it's trying to make you believe it is. But now, you find the same goofy, good-natured site you've come to trust, going “aw shucks” and apologizing cutely. The website is a friend, a person you can forgive, not a service that only fills a small niche in your wide array of needs.
In a world where social media is king, even websites are getting social. If you build a site that's easy to use and understand in all ways, more people are more likely to come back to it, to use it on a regular basis, to incorporate it into their daily lives.