Not very many are using Twitter, according to Pew Research.  Facebook and Linked In are far more popular.  Three fourths of us research product information online and 8 out of 10 seek medical information.

This infographic shows how adults are using the Internet for news, shopping, social networking, personal business and finance.

http://www.flowtown.com/blog/what-are-people-doing-online
Flowtown – Social Media Marketing Application