According to a poll of attendees at an Ad Age Digital Media Conference, Second Life was voted the most over-hyped media trend. While I have not found much interest in it personally, I have watched my son create avatars inside Club Penguin, Pirates Online, and to a certain extent, through Webkinz. Each allowed him to play in a virtual world and interact with others. Luckily for me, on a very limited level.
And while he sporadically goes to them, the impetus is the gaming, not the exploration. I believe for that reason, Second Life, as it stands today is over-hyped and is more fad than future. Content providers that create multiple platforms for their brands will find more success coming from these online worlds. Watch Hannah Montanah or Pirates of the Carribbean, then interact in their space. Move from TV to VOD to Wii to PC, but stay with the content. That loyalty can equate to revenue and allow brand messages to break through the clutter.