Today Wired.com published an article on how all the worlds that we are involved with in MMO's may someday interact and what it may be like.

Sometimes futurists get the future right. Millions of us now commute to mass­ively multiplayer online games in worlds much like the metaverse predicted by William Gibson, Neal Stephenson, and the Wachowski brothers. We live vicariously through our digital avatars in lushly rendered virtual environments, building and bartering, chatting and flirting, even falling in love. The population of the computer-generated universe is increasing at a rate that rivals email's growth 15 years ago. A decade hence, you'll drop a reference to your virtual doppelgängers just as casually as you give out your email address today.

You can read the whole article here