OT: Web board hackers

[Nazgul]

This is kind of OT, but I just discovered through google that the karate school I go to used to have a website (site has since changed) that had a web board of the exact same style of this one. Apparently somehow it was hacked and is currently being used for massive porn-related posts. Unfortunately info from our karate school is still on the site which links to the web board but is apparently somehow separate? I really don't understand websites that much which is why I'm posting this. It is really embarrassing for our school, IMO, to have our instructors' names posted on there and even for them to be registered users of this web board, which is currently being posted on hundreds of times per day by perverts. I mentioned it to an instructor last night and he says the site was shut down but can still be viewed by google, that there's nothing that can be done about it? Personally I don't get it and am wondering if anyone knows anything about whether even part of the situation could be fixed. I'd really appreciate any info anyone could offer.

Thanks a billion,

~Naz