Greystripe has been punting free mobile games funded by ads for some time now, through its own GameJump portal and its hefty network of B2B channels.

However, the company has revealed it's also making hay from using its technology to ad-wrap iPhone games. The company has passed 140 million ad-supported downloads, with 30 million coming in Q4 2008 alone.

More importantly, though, more than 50 per cent of its ad impressions are now coming from iPhone titles, according to TechCrunch.

What's more, Greystripe's top ten games by ad impressions are all iPhone games. The company launched new rich media iPhone ad formats in early December, including mini-advergames that sit within other titles.

It seems Greystripe may be shifting focus towards iPhone as a result, or in its words, making it "a priority for the foreseeable future". Other advertising firms, like AdMob, have been placing a similar priority on iPhone in recent months.