Google Inc. is stepping up its push to sell advertising on cellphones, announcing a deal Monday to buy a mobile ad network, AdMob, for US$750 million in stock.

Google already has a mobile ad delivery system, DoubleClick Mobile, which it got with its $3.2-billion acquisition of DoubleClick Inc. in 2008.

Google said buying AdMob will give it more expertise in a market that is expected to grow rapidly over the next several years.

Omar Hamoui founded AdMob in 2006. The company, which is based in San Mateo, Calif., provides a market for advertisers to buy space on websites geared for mobile devices.

“I’m obviously excited, and not only for our customers, partners, and employees,” wrote Hamoui in a memo to staff. “I’m excited because I believe this will be an important moment for everyone involved in producing, consuming, or monetizing engaging products on mobile. The truth is that the mobile industry has had no shortage of creative energy, amazing products, and talented entrepreneurs. But until now, it has always felt like those of us involved in this space played second fiddle to our online brethren. I believe that time is over.”

“Mobile advertising has enormous potential as a marketing medium and while this industry is still in the early stages of development, AdMob has already made exceptional progress in a very short time,” said Susan Wojcicki, Google’s vice-president of product management, in a statement.