comscore

The average Facebook user spends more than eight hours a month on the site, and many of us spend much, much more. What you might not realize is how much actual spending all that social networking leads to.

U.S. shoppers spent 15 percent more in online holiday buying compared to last year, after what may have been the busiest week of the season, said research firm comScore on Sunday. Shoppers have spent $30.9 billion online from Nov. 1 through Dec. 16, up from $26.9 billion at the same point last year, said the Reston, Va., company, which tracks Web use.

Best Buy is taking its best shot at stealing some online market share from Amazon.com with a completely new service meant to challenge the world's largest e-commerce company. Best Buy Marketplace will substantially increase the number of products available at the Best Buy website.

It's been heck of a ride on Wall Street: the ups, the downs, a 500-plus point selloff. But some stocks suffered far more than others this week. Here's a look at 10 of the biggest decliners.

Back in July 2005, the deal seemed so promising. Rupert Murdoch's News Corp bought MySpace parent Intermix Media for $580 million. The social media pioneer was, by some measures, the fifth most-visited website in the U.S. This week, MySpace was sold for a fraction of that amount.

Apple recently introduced iMessage, a new service that lets users send text messages, photos and videos between all Apple devices. This could challenge Research in Motion's BlackBerry Messenger service, which has been a unique selling point as the company struggles to compete with Google's Android and Apple's iPhone.

Research firm ComScore projects that spending on online-video advertising will more than triple between 2010 and 2015. But that doesn't mean you'll necessarily see more commercials per video. Spending will continue to lag behind the huge growth in online videos, according to ComScore.

Ever since rebuffing Microsoft's takeover bid, Yahoo has been keen to placate angry shareholders, and Carol Bartz's latest moves are doing that still. But by failing to keep up with true social networking a la Facebook, Yahoo risks losing its loyal audience.

Facebook ruled the Internet in 2010. It was both the most-searched term -- accounting for 2.11% of all searches -- and the top-visited website, attracting 8.93% of all U.S. visits, compared to Google's 7.19%.

As more shoppers spend their money online, retailers are deciding where to put their e-marketing. According to a new ForeSee study, promotional emails were still far more effective at driving traffic to retail sites than social networks like Facebook this holiday season.