Its a well known fact that secondLife has really taken off and made a hit with everyone that can pay for it. It is essentually one virtual world rather than many virtual rooms. I really wish Google would have taken this approach rather than just launch some embedled 3-d chat rooms.
There is so much more potential, if Google wanted to, it could take a majority of secondLife's users just by modleing after it except making many aspects of it free. Their was also the potential of virtual ads, virtual web browsing, and opening it up to developers to really (and I do mean really) play with. Right now it looks too unrealistic and childish.