Second Life: 5 million

Broke 5 million:

• "31,377 new signups bringing us to 5,011,608 signups total. The five-millionth signup took place between 2PM and 3PM today. Signup rates continue at their depressed level, and the six millionth signup is due in 28 days, on 24 May.
• A peak concurrency of 37,765 at 1:49PM, and a minimum concurrency of 18,440 at 1:40AM. Average concurrency for the day was 26,598.