I like Twitter, but I don't think it's the type of app that most people will actually use or at least it won't reach the popularity of a site like Facebook unless they make big changes.

 

Oprah isn't the only new user already bored with Twitter. In fact, about 60% of Twitter users quit after their first month, Nielsen Online estimates. The good news for Twitter is that its 40% retention rate is higher than it was a month ago. The bad news is social networking peers

 

http://www.businessinsider.com/60-of-twitter-users-quit-after-a-month-2009-4