Since it came into being as a geeky side project in 2006, Twitter has become "so muscular and ubiquitous that it now competes with the likes of Google and Facebook for users," says Claire Cain Miller in The New York Times. A new Pew study examines just who's tweeting. Here, a brief guide by the numbers:

Percentage of American adults that use the internet

Percentage of internet users on Twitter

Percentage of the total U.S. adult population on Twitter

Percentage of internet users who say they are "extremely active" on Twitter and use the service daily

Percentage of Twitter users who say they check for material posted by others several times a day

Percentage of tweets that are ignored. "For people who think a lot of fluffy stuff goes on on Twitter, this validates that," says Antone Gonsalves in InformationWeek.

Roughly half
Portion of Twitter users who tweet daily

Percentage of internet users on Twitter who live in urban areas

Percentage who live in the country

Dominant age range of Twitter users. Fourteen percent of those in this bracket use Twitter, while only four percent of those over 65 do.

Percentage of female internet users on Twitter, compared to seven percent of their male counterparts

Percentage of Hispanic internet users on Twitter, compared to five percent for white users and 13 percent for black users. Researchers did not have an explanation for why minority internet users are more than twice as likely to use the social media site.

310 million
Population of the entire United States

100 million
Number of Americans who are active on Facebook. "While the number of total Americans using Twitter represents a significant amount of people and highlights the importance of social media, it pales in comparison to the extent to which Facebook is used," says Dean Wilson in TechEYE.

More than 500 million
Number of active Facebook users worldwide, according to the company website

175 million
Number of registered Twitter users worldwide

About 370,000
Number of new Twitter users added each day

Sources:  New York Times (2), InformationWeek (2), TechEYE, ReadWriteWeb,