Interesting piece by David Rowan in The Times last month (I read everything after everyone else).

Apparently there are 15 million members of Second Life but there’s a good reason why the early adopters have moved on — it’s got too mainstream. Since big business (Coke, BT, Toyota) and governments set up shop there, it changed the nature of the site from sought-after cool to yesterday’s dull idea. Like Twitter, it became boring when everyone else started doing it.

Even so, its currency is stable and the game is profitable for its owners, Linden Labs. Much the same might be said for any cool brand; Twitter, eBay, Friends Reunited and Facebook swiftly became mainstream. But social networks need more than 100 users to generate the same revenue as that generated by a traditional media customer, such as a newspaper subscriber. With these figures, a site has to become mainstream to make any profit at all. Cool gets the attention, but only the continued visits of the rest of us will make it worthwhile.