Nearly all Americans make the vast majority their purchases near where they live and work, a fact that plays into the advantages of mobile commerce, according to the keynote speaker at Monday’s forum on Mobile Web & Apps at the Orange County Convention Center.

David Williams, vice president of mobile product development for AT&T Interactive, said people use the Internet to make long-range purchase decisions, typically taking a month to make a decision. When people use a mobile phone, they are more focused, looking for places to eat, movie theaters, gasoline stations or ATMs – searches done quickly, he said.

“It’s a lot more immediate,” Williams said, adding there is a strong business model to use mobile search as a tool to reach the local audience, especially as more people own and use smartphones with GPS built in. He said 93 percent of the purchases made by Americans are within 15 miles of where they live and work.

AT&T Interactive, a business unit of AT&T that grew out of paper business directories, expanded into an online directory linking businesses and consumers and now uses the Web as a “funnel” to get into mobile applications, he said.

Williams said AT&T Interactive uses both the mobile Web and phone applications to reach its two audiences. Both methods have their advantages, with the mobile Internet being less expensive and time-consuming, while apps are more persistent and targeted.

“We did both,” he said. “If we can catch you with the mobile Web, we can get you into applications.”

The future is bright for mobile commerce, Williams said, because of the growth of smartphones and their location awareness. Marketing and advertising to smartphones using text messages, application alerts or links through display advertising can become very powerful because of the ability to know a user’s location and personal preferences, he said.

AT&T Interactive has started using “HyperLocal” advertising that alerts phone users with coupons and other incentives based on their location.

Another speaker, Remco van den Elzen of the app store data firm Distimo, said free mobile applications are growing in importance. But he said there is a wide difference in how people access applications on a mobile phone versus a tablet. Gaming is very important to iPhone users but not so for iPad users, who also use productivity apps much more than iPhone users, he said.

There also is a big difference in the popularity of applications in various regions, van den Elzen said. Ninety percent of the mobile applications downloaded in Korea are not downloaded at all in the U.S.

“Few applications can be successful across all markets,” he said. “There’s a huge opportunity for local applications.”

A recent Distimo report said Apple is far and away the app store leader, with 300,000 apps in its iTunes store. Google’s Android platform finished last year with 130,000 apps, while Nokia’s Ovi store had 25,000 apps and BlackBerry had 18,000.