The Pew Research Center has published its latest survey into American internet use, focusing on social networks. It finds that 72% of US online adults are using social networking sites today. It also breaks that down by age group: 89% of 18-29 year-olds, 78% of 30-49 year-olds, 60% of 50-64 year-olds and 43% of people aged 65 or older. That latter group is up from 13% in the spring of 2009, incidentally. Pew’s survey also focused on the growth of Twitter, with its popularity doubling since November 2010. 18% of online Americans now use Twitter, although that rises to 30% for 18-29 year-olds. The latter figure is actually slightly down on the percentage who said they were using Twitter in August 2012, though. The survey was based on telephone interviews with 2,252 adults in April and May.