Inside Twitter’s “100 Million New Members” Number!

How many users does Twitter really have?

Last week, Twitter announced that it added 100 million new accounts so far in 2010. That’s a staggering number when you consider that six weeks ago it revealed it had signed up a total of 175 million new accounts since its launch and was adding new ones at a rate that would bring it to 200 million by the end of 2010. Translation: 50% of Twitter’s accounts were added this year.

On the flip side, the Pew Internet & American Life Project just reported that only 8% of US adult internet users used Twitter in 2010. According to eMarketer’s estimates, there were 178.6 million adult internet users in the US in 2010, so Pew’s figure translates to 14.3 million users. This number is lower than eMarketer’s April 2010 estimate of Twitter users, which will be updated in early 2011.

To be clear, Pew asked survey participants if they actually used Twitter, not merely whether or not they had an account. This is very different from Twitter reporting its total number of new or existing accounts.

Inside Twitter’s “100 Million New Members” Number