What do people spend the most time doing online? You guessed it, social media.

According to a report in Advertising Age, new research by Nielsen shows that the percentage of time American PC users spent on social media websites in June 2010 jumped to 22.7 percent from 15.8 percent in June 2009. The second-most-popular time-consumer is online gaming, which inched up to 10.2 percent from 9.3 percent, knocking e-mail down to No. 3.

Go here for the full Ad Age article:  http://adage.com/digital/article?article_id=145207