Twitter recently passed MySpace in unique visitors to become the number three social networking service in the world, according to last month's data from comScore (via Digits). Twitter had nearly 96 million unique visitors in August, up 76 percent from the same period last year, while MySpace dropped 17 percent during the same period, to 95 million unique visitors.

The four-year-old micro-blogging service is doing quite well when compared to the seven-year-old MySpace, but both are easily dwarfed by Facebook, which grew by 54 percent to 598 million unique visitors in August. In second place is Microsoft's Windows Live Profile, with upwards of 140 million visitors.

Twitter messages may be limited to 140 characters each, but the service still ends up storing up to 12 terabytes of data every day. "That would translate to four petabytes a year, if we weren't growing," Kevin Weil, Twitter's analytics lead, announced at the Web 2.0 Expo in New York, according to Technology Review.

Twitter recently had to deal with a major security flaw on its website that affected thousands of users. The company still doesn't have a strategy for a steady stream of revenue, but a recent post on the Twitter blog implies that media content will play a big part.