The Sale of MMORPG Items on Online Auction Sites? (Score 1)

I've heard varying responses to this one and would like some further input. Is it legal to sell items from MMORPG's like Everquest, Diablo 2 or Star Wars Galaxies to other players? If not, why has eBay not forbid these type of auctions since it is strictly against illegal material? Lastly, if this is illegal, would the auction sites selling these items be held responsible or the individual buyers/sellers of the items? Thanks.