Facebook is becoming the biggest advertising platform in the world

Facebook is the second most visited website in the UK, accounting for 7.14% of all internet visits in July, according to Experian Hitwise.

Facebook is a never ending story of growth, with no sign of slowing. Well, no real fool-proof sign, anyway.

The social networking king also accounts for over half (54.48%) of all visits to social sites.

In terms of total visits, Facebook continues to trail Google UK, and recorded a 9.59% market share in July. However, using the measure of total page views rather than visits, Facebook is way ahead.

As the table below illustrates, the social network accounted for 16.73% of UK page views during July. In other words: last month, 1 in every 6 Internet pages viewed in the UK was a Facebook page.

There are 26 million British users already and Facebook’s market share of UK page views has trebled over the last five years. However, growth has slowed significantly over the past six months having grown around 1.7% since November last year, compared to a sizeable 5% growth between April and October last year.

As Facebook continues to grow around the world (last month it reached more than 500 million registered users, some are beginning to wonder when the site will reach saturation point.

Recent government statistics put the amount of adults online as 37.4 million, so the site still has a few more people to entice in with the thrills of Farmville. But it must also find a way to entice users to spend long amounts of time on the site if it wants to entice more advertisers.

The average session time on the site has leveled out to around 27.36 minutes in June/July, down from a seasonal peak of 30 minutes in December, says Experian Hitwise. This is still a good deal better than most other sites out there.

And there’s no doubt that big brand advertisers are getting on board. Facebook revenues are tipped to double to $1.4 billion (£885m) in 2010 as advertising fees continue to surge.

According to Facebook COO Sheryl Sandberg, the biggest advertisers increased spending by as much as 20-fold in the past year. In an interview with Bloomberg she said: “Two years ago the big brands were experimenting with us. Now, they’re going big.”

Facebook is also improving its infrastructure to give more space and time to display advertisements and increasing user personal engagement with brands through social gaming and other features.

Facebook marketing has been used to improve reach for online clothing retailers, revive Buick Motor’s youthful spirit, inspire the electric car market, boost revenue for Old Spice and increase pizza delivery orders at Dominos Pizza.

Things won’t slow down either, as Facebook eyes expansion in developing BRIC countries that could double that ‘500 million’ figure.

There’s no denying that Facebook is on its way to being the biggest advertising platform in history…