Research firm The Kelsey Group projects local mobile search advertising to grow from $20 million in 2008 to $1.3 billion in 2013, a compound annual growth rate (CAGR) of 130.5 percent.

This mark bodes well for local marketing. "As mobile data consumption rises, we expect local marketing to be a big winner," said Michael Boland, program director, Mobile Local Media (MLM), The Kelsey Group, in a statement. "There is a strong correlation between local search and the mobile use case, which will cause a good portion of the ongoing mobile application boom to focus on local."

Kelsey also reports that the 54.5 million mobile Internet users in the United States comprise 25 percent of online users.

In addition, 15 percent of iPhone applications are local, according to the research firm.