I was surprised and disappointed to see that Project Euler was offline, as of yesterday. The message they’ve posted on the home page makes it sound fairly serious, and it doesn’t sound like they’re 100% sure they’re going to be able to bring it back up any time soon.
I can’t understand why anyone would hack into something like Project Euler. It’s free, so there’s no money involved, and no credit card numbers to steal. It’s not political, so there’s absolutely no ideological reason to want to bring them down. And it’s not popular enough to the point where a hacker would do it just for the media attention.
I guess there might be some value in their password database, but I think most of their users would be internet-savvy enough that they wouldn’t likely be using the same password across multiple accounts. And if that’s what they were after, there must be better targets for that than Euler.
Their forum site is still up, and there’s some discussion about the problem here, but no information from the admins as of yet. And there’s a thread on reddit talking about it, which includes links to some other interesting programming puzzle sites.