Several social networking sites, serving at least 10 million monthly visitors, underwent dramatic growth during the past year, according to a comScore study on the expansion of social networking across the globe, writes MarketingCharts.

Among comScore's data on select sites' year-over-year growth and visitation numbers:

• Social networking behemoth MySpace.com attracted more than 114 million global visitors age 15 and older in June 2007 - a 72 percent increase from a year ago.
• Facebook.com experienced even stronger growth during that same time frame, jumping 270 percent to 52.2 million visitors.
• Bebo.com (up 172 percent to 18.2 million visitors) and Tagged.com (up 774 percent to 13.2 million visitors) also increased by orders of magnitude.

• MySpace averaged 28.8 million visitors daily in June 2007 - 72 percent more than a year earlier
• Facebook's average of daily visitors exploded 299 percent, reaching 14.9 million in June 2007 from 3.7 million a year earlier.

"Literally hundreds of millions of people around the world are visiting social networking sites each month and many are doing so on a daily basis. It would appear that social networking is not a fad but rather an activity that is being woven into the very fabric of the global internet," said Bob Ivins, executive vice president of international markets.

MarketingCharts has more data here.