The mobile advertising pioneer is a Silicon Valley success story that emerged in 2006, when Omar Hamoui founded the company after being frustrated by a lack of ways to generate traffic for his mobile site, claiming it was too hard to engage users.

“I’ve been working in mobile for over seven years now. Before AdMob, I founded two separate mobile startups that never got significant traction. It was so frustrating to build what I knew was an incredible service only to find myself unable to distribute or monetize the product without a carrier or handset deal. Turns out, I wasn’t the only one. Talk to any veteran in mobile and they will tell you just how hard it was to get things done only a few years ago,” wrote Hamoui in a statement.

These days AdMob is serving targeted and personalized advertisements on the mobile web through the use of its mobile advertising platform. According to the company website, the network claims to have served over 125 billion impressions.

The acquisition is the fourth biggest publically-disclosed deal in Google’s history, at least if Wikipedia’s metrics can be trusted. Upstaging the AdMob deal in price tag is the landmark $3.3 billion (US $3.1 billion) the company paid for DoubleClick, plus the $1.8 billion (US $1.65 billion) shelled out for YouTube and the cool $1.08 billion (US $1 billion) paid for a 5% stake in America Online – more commonly known as AOL – back in 2005.

Word also leaked that Google is rumoured to be acquiring Gizmo5, which was swallowed up in the hype surrounding the AdMob deal. The search giant is allegedly writing a cheque for US $30 million for the VoIP startup, though no official confirmation has come through yet.