The latest study from research firm Pew Internet puts Twitter usage among "online" adults from the US under the microscope. Findings show that 15 percent of respondents used Twitter as of February 2012 with 8 percent doing so on a daily basis.

The number of people that use the service on a daily basis has doubled since May 2011 and quadrupled since late 2010. The researchers note that the rise of smartphone usage likely influenced the influx of Twitter users. In fact, one in five cell phone owners between the ages of 18 and 24 used the service on their phone with 15 percent doing so on a typical day.

As we have seen in other Internet-related studies, there's a noticeable trend with relation to the type of people that use Twitter. The number of men versus women that use the site is virtually identical although women do slightly edge out the guys. Stats show that people ages 18-29 are the heaviest users with nearly double the number of users as the next largest group (30-49).

Data further highlights that Twitter usage is more prevalent among African Americans, households with an income less than $30,000 a year, those with no high school diploma and individuals living in urban and suburban environments.

Data for the tracking survey was gathered between January 20 and February 19, 2012 from 2,253 adults age 18 or older via telephone interviews conducted by Princeton Survey Research Associates International.