The world of mobile and iPhone advertising has received a significant shakeup with the news that Google has entered a definite agreement to buy mobile network company AdMob for $750 million in stock.

It's a huge valuation for a company that was founded in 2006 but has only taken off with the release of the iPhone.

After Google, AdMob is the largest mobile advertiser. It claims to have served over 1.25 trillon ads to date.

Of course AdMob founder and CEO Omar Hamoui is in ebullient mood and has posted a long explanation of the deal on the AdMob website.

"After our deal with Google closes, we will work together to accelerate the pace of innovation in this area," he says.

"Obviously this transaction represents only a part of their [Google's] overall interest in mobile but all of us at AdMob are looking forward to working with them to make sure that the future of mobile is no longer so far away."

AdMob acquired iPhone in-app advertising mediation company AdWhirl in August; a deal that Michael Chang, CEO of rival GreyStripe criticised as being a conflict of interest.

Certainly it will be interesting to see what the reaction to this deal is considering Google's overwhelming dominance in the online advertising space, particularly if it encourages other large media companies to enter the fast moving mobile advertising space.