I agree with inshaala:
"...you could take it as a compliment, they thought you were good enough to "steal" ;)... " even if what they did it's terrible IMHO.
I would be curious how many images have been stolen, but I don't want to register in a web site where stolen pics are posted with other names authors...so I'll keep my curiousity...but
I found "gdmora" account here, but as often happens he/she has not a gallery, not an e-mail adress or the chance to send him/her an IM...
So like a "fake" account done just to see and "stel" it seems....
It happened also that people create account like this one to leave bad comments or speak badly about people here...I think that there should be the chance to get in touch with these people...it's not right they have the chance to write and do what they want and artists has no right to reply...
Perhaps there should be a limit: if you want an account you have to post something (time limit 1 week for example for new user) if you won't post anything in this time your account will be cancelled...and of course obliged to leave an e-mail adress or being reacheble by IM...
I think it's too comfortable to be a ghost and do what you want...IMHO.

Anyway  I'm sure Renderosity stuff will do it's best to do something!
Lara