Well, on my opinion stealing it's illegal but on the sites where it happends. But it's a catch: let's put on example Neopets.
Okay, if you steal on Neopets you have consecuences in the site, which is the obvious thing to happends.
When you steal on a bank account you have real life consecuences becouse it's real money involved...
But nobody counts that on Neopets, people use real money. And for example, if I hack an account and steal their NC items, that would be similar to steal real money from them... but anyway, that only has consecuences on Neopets and no police will go after me to chase me.
You know? it's a little stupid. But the true is that the value of virtual goods is not a thing (at least in most of countries), they are not real things and cheatinh and hacking on virtual games isn't against law... but I really think that with time passing, this goods will have a real life value when the society understands the importance of virtual items that were gotten with real money.