http://bentasker.i2p/posts/documentation/security/290-hosting-tor-hidden-services-onions.html
TOR is a useful tool for anonymity, but it's not a panacea, high-profile takedowns (and arrests) do happen in relation to Hidden Services. For examples, see the take down of Silk Road , Silk Road 2.0 , DoxBin and various other examples. If the .onion you're planning to run is anything more than a small personal site, give it serious thought before setting anything live!