Users can report content on FB (photos) as inappropriate (sexual, copyright, violence, etc). They almost certainly have some automatic system behind that automatically deletes content that receives enough "votes" (or maybe votes from trust-worthy users). I'm guessing that this is what happened to you.
I think that something similar (they banned our whole domain) also happened to us last year (http://news.ycombinator.com/item?id=2527955), and I still don't know who fixed it or if it was just a glitch.
You will note that I've used a lot of "I think"s, there's a reason for that, nobody (except for FB obviously) actually knows the rules of the game :/
Did they let you know what the inappropriate content was? When your page was restored was the history and content intact? Aren't you concerned it'll happen again?
Re:When Facebook Disables Your Fan Page
by greenwalls on Thursday October 04, 2012 @02:48PM
(#4613725)
They never let me know what the inappropriate content was. The page was restored with all the history/content intact and all likes intact. Yes I am very concerned and paranoid it could happen again and I've really locked down my page a lot more that I probably would have otherwise. For example I don't let users post to our wall anymore, they can only comment on our own posts.
Even before we were mysteriously blocked I never let users post photos/videos to our wall and obviously we'd never allow any inappropriate content there.
Facebook said we had posted inappropriate content but I was the only one with admin access and I'm absolutely 100% sure that never happened. Also the page was set up so users couldn't post images.
I think what must have happened was they had some kind of temporary exploit where someone was able to post inappropriate content that looked like it came from us, or maybe users were able to post something temporarily somehow. Or I guess it could have just been a glitch and nothing bad ever happened at all and that's why they reinstated it? It was very stressful but I'm glad it's over now.