Annual revenues of mobile search services are expected to reach $4.8 billion by 2013, Juniper Research firm has predicted in a study.

Some of the factors driving the growth include the decline of carriers' "walled garden" approach, falling data costs and the entrance of search giants such as Google and Yahoo.

For advertisers, local search will be the most popular service, which will bring in 40 percent of mobile search ads over the next five years. When broken down by region, China and the Far East will be the biggest contributors in the coming years, followed by Western Europe and North America, Media Post reported.

However, Juniper warned that an "advertising overload" in mobile search could alienate consumers. It also pointed out a rising concern over the use of personal data gleaned from mobile search.