Fifty-one percent of Americans ages 12 and up have Facebook accounts, says Edison Research, which will release a full report on its findings in a webinar on April 5.

Edison has been tracking the growth of Facebook since 2008 and says the site was only used by 8 percent of Americans of the same age just three years ago.

According to Facebook's official numbers, there are more than 500 million people on the site worldwide. That's about the same as the combined population of the European Union. Since 2008, Facebook usage has increased, especially among people 35-years-old and up, the study says.

Source: PCMag
http://www.pcmag.com/article2/0,2817,2382680,00.asp