Compared to user activity on social networking sites last year, Facebook and Twitter posted gains of 69% and 45% respectively in the U.S. Globally, the total minutes spend on social networks monthly saw a more than 100% gain over the same time last year.

As sites like Twitter and Facebook continue to grow, global consumers spent more than five and half hours on social networking sites in December 2009.

If you’re in the U.S. and are using a social network like Facebook, Myspace or LinkedIn, chances are you’re more affluent and more urban than the average American.

Top social networking sites like Facebook and LinkedIn may be well-established, but that doesn’t mean they’ve stopped growing.
Nearly half of the biggest social networking sites are also among the fastest growing, according to data released Wednesday by Nielsen Online.
These top sites have also expanded beyond the youthful audience the social networking space initially captured — to find a place in older visitors’ professional lives.  Facebook, LinkedIn, and Reunion.com are most popular among visitors ages 25-34, 35-49, and 55-64, respectively, Nielsen reported.

Rank
(by Sept. YOY UA growth)
10 Fastest Growing
Social Networking Sites: Sept. 2008
Sept. 2007:
Unique Audience …