Matters like these usually depends on the circumstances i.e. how big the site is, where it's hosted etc.. What are your intentions with it? I don't know what country you live in but in most contries the specific Torrent sites aren't illegal, it's the sharing of the files that the torrents link to that are illegal.
I can't see why, as long as you took down all the dodgy stuff fast. Having said that, *I* wouldn't unless I'd taken pro legal advice first.