Personally I don’t have a lot of time for gaming and virtual worlds, but perhaps as these virtual worlds develop, they will become more mainstream and perhaps we will be going to these virtual worlds to do our shopping, whether for consumer goods or groceries (much like going to sears.ca). This concept may also work for libraries. It all seems rather scifi, but who knows?
My fear is that this sort of development will encourage social solitude rather than live social interaction.
As for gaming, I think it can be used to develop user skills, whether physical or mental dexterity, and knowledge through producing “interactive games” to help students learn.