Annual revenues from mobile search services are expected to hit $4.8 billion by 2013, according to a new report from Juniper Research. Among the factors driving growth are the decline of carriers’ “walled garden” approach, falling data costs and the entrance of search heavyweights such as Google and Yahoo.

Local search will be the most popular service among advertisers, attracting 40% of mobile search ad spending over the next five years. Globally, China and the Far East are expected to generate most revenues from mobile search in the coming years, followed by Western Europe and North America.

(via Online Media Daily)

Related update: Matt Waddell, a product manager for Google mobile said in a Reuters interview: “We have very much hit a watershed moment in terms of mobile Internet usage. We are seeing that mobile Internet use is in fact accelerating.”

Second related update: M:Metrics reports on iPhone feature usage: “Two featured widgets, YouTube and Google Maps, are extremely popular among iPhone users: 30.4 percent accessed YouTube and 36 percent used Google Maps. In comparison, only one percent of all mobile subscribers accessed YouTube and 2.6 percent checked out Google Maps.”

What it means: more indication that local mobile search is about to happen.