Twitter has more than 105 million registered users. The tally: 105, 779, 710 is significantly more than outside analysts had estimated. The company also says it's adding 300,000 accounts per day with much of its growth coming from outside the United States. The number doesn't address how many of those accounts are active. It comes after month of outside speculation that the number of monthly visitors to Twitter's main page had peaked after astronomical growth in early 2009. Twitter is a social networking service that enables its users to send and read messages known as tweets. Tweets are text based posts of up to 140 characters displayed on the author's profile page and delivered to the author's subscribers who are known as followers. Take any celebrity. Take John Legend, he has 1,808,572 followers on Twitter. His most recent tweet was:

in the studio working on #wakeup2010 w/ @questlove and @puddyakalef2th http://twitpic.com/1ffrbt

When you put '@' in front of something and you type in the name of another account, you tag them in a post which notifies the user. There is even a Twitter page for Twitter itself. So, if you want to know what your favorite celeb is up to, join Twitter today, and tweet away!