SAN FRANCISCO - Google announced Monday it is buying smartphone ad specialty firm AdMob in a US$750 million (S$1 billion) stock deal.

Google hopes AdMob will help it more effectively extend its lucrative Internet advertising domain into the booming world of mobile devices.

"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 Google vice president of product management Susan Wojcicki.

"AdMob is the quintessential Silicon Valley startup -- generating impressive year on year revenue growth -- and we're excited to welcome this talented team to Google."

AdMob was founded in 2006 by Omar Hamoui as a California technology startup focused on building tools that let Internet advertisers follow potential customers onto mobile devices.

Hamoui reasoned that the more advertising dollars that flow onto the mobile Internet, the more creative offerings will flourish in that environment.

"I think people underestimate how important ads have been to funding the development of innovative content on the Internet," Hamoui said.

"Our goal all along at AdMob has been to make it possible for developers and publishers to bring their products and ideas to mobile with the same business model."

Google said it plans to work with AdMob to enhance ways advertisers can "engage" mobile device users and website publishers can make money in the smartphone arena.

"As publishers and developers generate more revenue from their mobile products, they will invest more, and their mobile offerings will become richer, more creative and more robust," Hamoui said.

"We're proud of the progress we've made towards accomplishing this goal, and joining Google will only accelerate this process, ultimately leading to very real benefits for end users around the world."

People will ultimately see more ad-supported content and applications on smartphones if Google's vision of AdMob's future proves true.

"Google forges ahead in mobile advertising," said Forrester analyst Neil Strother. "They already had mobile AdSense, but this gives them a different angle."

Google AdSense lets marketers target ads based on keywords used in searches on Internet-linked mobile devices in much the same way that the Mountain View, California-based Internet powerhouse aims ads at computer users.

AdMob has an established display advertising network for smartphones, particularly Apple iPhone devices that have been a global hit.

"The iPhone has been a boon to AdMob, so now Google gets to play in that space," Strother said. "It could be Android, Windows Mobile, or any other platform."