Twitter has 175m registered users

"In a New York Times profile on Twitter co-founder Evan Williams, the company revealed a few interesting stats showing the growth trajectory of the network. Twitter now has 175 million registered users, which is up from 145 million users in September. That means the startup added around 30 million users in just under two months. And Twitter has added 70 million users since April.
This is impressive growth considering that Twitter had a total of 58 million users in 2009 (and 503,000 users three years ago). That’s a 200 percent increase from 2009 to 2010 in terms of users. And the year isn’t over—it’s conceivable that at the rate Twitter is growing, the company could be ringing in the New Year with 200 million users. So what’s contributing to this massive growth?"

Source:  Article in the New York Times, reported by Techcrunch, 31st October 2010