5 of the top 10 markets where most time is spent on social networking sites are in Latin America

"Latin Americans are strongly engaged with social networking. Half of the top 10 worldwide markets ranked by time spent on social networking sites are in Latin America, with Argentina leading the region at 10 hours per month in June 2011.
The Latin American social networking audience is nearly equal in its composition of males and females, but females account for a larger share of social networking time spent (53.6 percent) compared to males (46.4 percent). This trend was most significant in Brazil where females accounted for 58.7 percent of all social networking time spent.
People age 15-24 demonstrated the strongest engagement on social networks, accounting for nearly half (48.0 percent) of all time spent in the category. This trend was most significant in Venezuela where visitors age 15-24 accounted for 3 of every 5 social networking minutes (58.2 percent).
Facebook.com strongly led the social networking market in Latin America, reaching more than 91 million visitors. Windows Live Profile ranked #2 with more than 35.5 million visitors in the region. Orkut held the #3 spot with 34.4 million visitors, largely driven by the site’s popularity in Brazil, while Twitter.com ranked #4 with 24.3 million visitors.
Five of the top 10 markets ranked by Facebook.com reach are in Latin America. Facebook reached 90.9 percent of all online users in Chile, ranking as the most penetrated market in Latin America.
In Brazil, Orkut ranked as the most-visited social networking destination, reaching 35.7 million visitors, an increase of 20 percent from June 2010. Facebook.com, which is the second largest social networking site in Brazil, witnessed strong growth increasing 192 percent to 24.5 million visitors.
Venezuela is the only country in Latin America in which Twitter.com rises to second place in the social networking ranking. One in four online users in Venezuela visited Twitter.com in June (26.5 percent reach).
Recently launched Google+ reached 28 million visitors worldwide in the first 33 days of its public existence (June 29, 2011 to July 31, 2011). Brazil ranked as the sixth largest market for the site globally, contributing 793,923 visitors."
Source:  Press release from comScore, 20th September 2011