Pew Internet & American Life Project is a nonpartisan, nonprofit "fact tank" that provides information on the issues and trends shaping America. They are a wonderful resource for data and statistics and recommend checking out their website. If you look at this table, it makes sense that age is the biggest predictor of social media use. I highlighted in red some of the social media activities.
New content and information are required to “feed the beast”
You can think of it as an instant message that goes out to lots of people. It can be mundane but it can also be a powerful tool to share information and build relationships. 8% of the American adults who use the internet are Twitter users. It’s particularly popular with young adults, minorities, and those who live in cities.
Legal Aide Society
Most visited website in 2010 per Hitwise . Fastest growing group is women over 55 years old