TechCrunch posted a new update with Second Life stats:

- Registered users are up to over 3 million, up from 124,000 a year ago (closer to 2 million when you remove duplicates)
- At any given time between ten and thirty thousand people are online

- They currently have 258 islands generating between $200 - $300/month in hosting fees

The biggest hurdle they have is the relatively low number of people online at any given time, which really is interesting considering the amount of money being spent in-world daily ($1.1 million as of this posting).