Just got done reading TechCrunch's post on Second Life Census Metrics (where you can also download a spreadsheet with all the data) and my original predictions about the population of Second Life reaching 7 million by the end of this year are realisable (and I'm looking at the actual registered users - deduped).

Sure, there are multiple avatars for some individuals, that's why I charted them both, side by side.  Infact, there's probably an "engagement metric" you can get out of the widening gap between unique individuals who have registered and the number of avatars existing in Second Life.  More and more people are creating 2 or more avatars and that spells Engagement and more time being spent online in Second Life.

The population by country makeup is also telling, most being the G9 countries, it's US and then France (the French always liked "Sexy" games).

Of course, these "Census" numbers released by Linden Labs are far from the metrics that each Island, Each Business, each Avatar could have.  I'm in the process of trying to contact ElectricSheepComany.com to find out what they have to offer.  Hopefully, I'll get a hold of someone one over at ElectricSheep one of these days.