Facebook grows up

This was the year of the Facebook mom and grandma. Founded in 2004 for college students, the online social network exploded in 2008 and might have been expected to level off this year. Instead, it went global and expanded into new and older demographics.

About 70 percent of Facebook's users now live outside of the site's home base in the United States, according to statistics released by the company.

The site's importance in our lives grew in tandem with these demographic shifts. Facebook now has more than 350 million users -- that's more people than live in the United States and is more than double the 150 million people who were on Facebook at the start of the year. Half of Facebook users log on to the site at least once on any given day; the average Facebook user spends nearly an hour a day on the site.