In December 2008 the 18- to 24-year-old age group accounted for 19% of Twitter users. In September 2009 that figure has leapt to 37% with 25- to 34-year-olds also rising swiftly from 20% to 31%.
The reports said that age is a strong independent predictor for use of Twitter and other services with a status update feature. Overall, internet users age 18-44 have rapidly taken up Twitter over the past nine months whereas internet users ages 45 and older are slower to adopt.
The research also found that the more devices people have the more likely they are to use Twitter. Around 40% of internet users with four or more internet-connected devices (such as a laptop, cell phone, game console, or Kindle) use Twitter, compared to 28% of internet users with three devices, 19% of internet users with two devices, and 10% of internet users with one device.
The same is true for wireless connections. As of September 2009, 54% of internet users have a wireless connection to web via a laptop, mobile phone, games console or other mobile device. Of those, 25% use Twitter or another service up from 14% of wireless users in December 2008.
The Pew report said: "Statistical analysis also shows that wireless access is an independent factor in predicting whether someone uses Twitter or another status update service.
"It is not simply because this group is likely to be young or tech-savvy. Owning and using a wireless internet device makes an internet user significantly more likely to tweet."
As Facebook spreads its user base to a broader cross spectrum of society the transition of MySpace to an increasingly youth and entertainment centred social networking site continues apace. The average age of its users fell from 27 to 26.
Facebook was the only social networking service sited by the research to see the average age of its rise. Professional social networking site LinkedIn like MySpace also saw its fall 40 to 39.
The research also found that Twitter attracts users of other social networking sites. Those already using MySpace, Facebook or LinkedIn are likely to also use Twitter: 35%, compared to 6% of internet users who do not use such sites.
The Pew Internet survey is based on data from telephone interviews conducted by Princeton Survey Research International between August and September 2009, among a sample of 2,253 adults who were 18 and older.