Actually I was half right, not WRONG 100%
If someone owns a .com name, you can register the same name with .net, as long as your don't copy their site or idea.
thehun.ru is in violation.
However lets say someone buys the domain: "elephantlist.net" and turns it into a website listing different breeds of elephants. (A real non-adult site)
The owner of elephantlist.com would have a hard time if he wants to sue.
Modified: After I made this post I tried to type in "elephantlist.net" and sure enough someone owns it, and it directs to a listing of pornsites. Is that illegal?