It's become clear recently that free iPhone and mobile games can still provide their developers and publishers with a very healthy revenue stream.

This is mostly thanks to the inclusion of mobile ad providers such as AdMob, which announced over the weekend that it's served its 100 billion mobile advert - that's 14 adverts each for every person on the planet.

The company is its massive growth down to the evolution of mobile websites and the introduction of the iPhone and smartphone application.

"What has made this adventure even more exciting for us has been growing alongside the explosion of smartphone devices that have redefined the mobile ecosystem," the AdMob official blog states. "Mobile has gone mainstream and the developments we’ve seen have been simply staggering."

Having only launched in 2006, AdMob's growth saw a massive increase beginning in June 2008 with the launch of the iPhone's App Store, with monthly ad requests across its network more than doubling to 8.3 billion.