Here's one of those penultimate rankings that nobody would have even imagined 10 years ago. While YouTube remains the number one source for video file sharing on the planet, it will probably soon have a second-runner up: Facebook (News - Alert).

YouTube , which is owned by Google, needn't worry too much, however, as Facebook is still is distant runner up. And Facebook hasn't quite surpassed the traditional number two for video sharing, VEVO a music-video Web site that is jointly owned by Sony Music Entertainment, Universal Music Group (News - Alert) and Abu Dhabi Media, and supported by EMI content licensing.

Business Insider is reporting that ComScore, which measures Internet traffic, discovered that in July of this year, 51 million people watched a video on Facebook. This figure is up more than 3.5 million from the previous month alone.

The figure, while impressive, is still one third of that of YouTube (News - Alert), which drew 158 million unique visitors during the same period. VEVO followed with 62 million uniques. However, at current growth rates, Facebook is expected to surpass VEVO by year's end.

While an increasing number of people are watching video content on Facebook, according to Business Insider, its users aren't particularly engaged in the video they watch. Facebook video watchers viewed only 17.9 minutes of video on average for July, the worst of all the top 10 video sites.

Analysts believe that if Facebook achieves the number two position, it's largely because of the site's colossal penetration worldwide, and its 162 million unique visitors to its site in July alone.

Quantity rather than quality, as they say.

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