Hmm... can see a whole new area of commercial exploitation springing up here... imagine wandering into town in your favourite MMO to see emblazoned across the side of the bank a giant "Hungry? A big-mac is only a /mcdonalds away" billboard.
Its already started Tenz, there are huge Burger King bill boards when you drive about in Need for Speed Underground 2, with BK signwritten cars and nonsence like that.