Nineteen percent of Internet users surveyed in August and September said they use Twitter or another service to share updates about themselves, the Pew Internet and American Life Project said.
That was a significant increase from previous surveys in December 2008 and April 2009 when 11 percent of Internet users said they post status updates, according to the Washington-based organization.
Pew said 35 percent of Internet users who already use a social network site such as MySpace, Facebook or LinkedIn are likely to also use Twitter compared to six percent of Internet users who do not use such sites.
The Pew survey also found a relationship between the number of devices a person owns and their likelihood to "tweet."
Thirty-nine percent of Internet users with four or more Web-connected devices, such as a laptop, a cell phone, a game console, or a Kindle, use Twitter, compared to 28 percent with three devices, 19 percent with two devices, and 10 percent with one device.
Thirty-seven percent of Internet users aged 18 to 24 use Twitter or another service, up from 19 percent in December 2008, the study found, while the median age of a Twitter user is 31.
The Pew survey found that the median age for an Internet user is 41 years old, the median age for wireless Internet users is 37 and the median age for a social network site user is 34.
The median age for MySpace is 26, down from 27 in May 2008, and the median age for LinkedIn is 39, down from 40, while the median age for Facebook has gone up to 33 from 26 in May 2008, Pew said.
The survey of 2,253 adults aged 18 and older was conducted between August 18 and September 14 and has a margin of error of plus or minus 2.3 percentage points.