Second Life was all the rage but now has become much less prominent. Habbo Hotel type metaverses seem to be thriving, as MMO games are also. Where are virtual worlds headed in next 3-5 years?
The initial excitement about VWs being the next advertising platform were premature - though this will happen over time. Many of the newer platforms are more focused on either 1. "pay to play" models that sell virtual goods and/or subscriptions or 2. sophisticated next-gen intranets that organizations like IBM are using to migrate a lot of their enterprise learning activities.