More than 13 million hours of video were uploaded in YouTube, during 2010 and 35 hours were uploaded every minute. However, YouTube, the video sharing Web site that used to be the world's largest source of Internet traffic, is losing its marketshare in the Internet populace.

YouTube, sold by its founders to Google Inc. for $1.65 billion in November 2006, is the third most visited website on the Internet, behind Google and Facebook.

YouTube, a video sharing site, on one hand and Facebook, a social networking site, on the other, are expected to coexist in the marketplace. But Google, which owns, YouTube, are battling for billions of advertising dollars.

The battle between the two Internet giants is for real. Just last week, it confirmed that Facebook Inc. hired a prestigious public relations firm, Burson-Marsteller, to persuade reporters and bloggers to write negative stories about Google's privacy problems. And software giant Microsoft Corp. has joined the fray -- in a bid to cut into Google's dominance in the search engine arena, Microsoft announced that Bing the search engine that would display personalized results based on what trusted friends recommend on Facebook, the world's most popular social network.

Possibly giving a concern for Google is the exponential rise for Facebook's display ads. According to market researcher comScore, Inc., Facebook served 346 billion display ads in the first quarter, grabbing nearly one-third market share to lead Yahoo, Microsoft, AOL and Google. Google, the overwhelming leader in text-based search ads with 95-plus percent of the market, rounded out the top 5 with a modest 2.5 percent share on 28 billion display ad impressions.

YouTube is also facing competition from sites that offer subscriptions to movies and videos via streaming. On the basis of Internet traffic, according to market researcher Sandvine, YouTube trails Netflix, a 23 million-member an online paid movie streaming provider, in North America. According to the market researcher's study, Netflix accounts for 29.7% of peak downstream traffic compared with only 11% for YouTube and only 1% for Hulu.

Early this month, in a bid to fend off competition from online movie rentals, YouTube said it is adding around 3,000 new movie titles for rent, though the service is only available in the U.S.However, Netflix is not resting on its laurels -- just yesterday, Netflix announced that hundreds of Miramax movies will soon be available to subscribers.

So what's next? YouTube's battle continues.