A 404 error is the error you receive when you try to visit a webpage that no longer exists and that the website has no replacement for. The 404, and other errors like it, are called HTTP status codes.
404 error pages can be customized to be more helpful, for instance with links to a website's top content. Some 404 pages even have games, videos, or other fun ways to entertain or get you more interested in something else on the site.
Invoking that "why didn't I think about that" reaction, like so many great ideas on the Internet, someone had a pretty good idea for utilizing that 404 page: turn it into a poster for a missing child.
So instead of showing a mostly meaningless error, or a list of links you weren't really interested in anyway, you see a picture of and information about a missing child. And here I thought the milk carton idea was a good one.
You can read more about this initiative at notfound.org. My understanding is that this is only available to websites in the EU.
What do you think about this? Do you think this will actually help? When was the last time you actually saw a 404 error?