Second Life is dead. Google just launched its own "virtual world" platform : Lively. The difference with SL ? Lively is entirely Web-based. You don't need to install and run a standalone piece of software, as opposed to Second Life (how many of us have been rapidly fed up launching SL ?...). To play with Lively, you just stay with your favorite browser, aka Firefox 3 (it runs with IE too).
Lively is truly the signal most of us were waiting for to go investigate the potential of Virtual Worlds for business. And it's made by Google.
For a complete review on Lively here by Techcrunch.
Download Lively here. That's the only thing that sucks, by the way : there's no Mac version for the time being, although Mac users are among the most efficient beta testers because we easily become early adopters...