According to MediaPost, global mobile advertising spending will grow from $2.7 billion in 2007 to $19.1 billion in 2012, mainly on the strength of text-message campaigns, according to a new eMarketer report.

Here in the U.S., mobile ad spending will jump from $878 million in 2007 to $6.5 billion by 2012, but will be eclipsed by the more mobile-centric Asia-Pacific market by then, the report said.

Text messaging still wins, since advertiser-linked SMS and MMS messages work on just about any recent cell phone, and don't require expensive unlimited data plans for browsing the mobile Web or viewing video.

In fact, the report said that response rates to SMS text-based ads have been far higher than those on the desktop Internet, reaching 12 percent in the U.S. We wonder how much of that is people responding just so they know who to complain to when they receive unwanted text charges on their next bill.

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