U.S. to top the world in mobile ad spending for the first time

Every year, for the past few years, marketers have been insisting that ‘this will be the year of mobile.’ Well, it looks like this year might actually be a high watermark for mobile advertising in the U.S. in some kind of quantifiable way.

For the first time, the U.S. will spend more on mobile advertising than any other country, including Japan, which had been the reigning leader, eMarketer said Wednesday.

According to the research firm’s forecast for worldwide mobile ad spending, advertisers will spend more than $6.43 billion globally in 2012, with the U.S. contributing $2.3 billion and Japan following with $1.7 billion.

“The big underlying reason is that smartphone growth and mobile Internet usage is growing very quickly in the U.S. and  you’re starting to see a tipping point where a majority of people are starting to use smartphones… or mobile Internet,” said Clark Fredricksen, vice president of communications for eMarketer. “That’s causing a lot of interest from advertisers.”

Additionally, he said, the increase in mobile spending is stemming from the fact that many advertisers in the U.S. already spend heavily in digital and are moving more money into mobile and from consolidation among U.S. ad publishers (for example, Google’s (s GOOG) purchase of AdMob and Apple’s (s AAPL) acquisition of Quattro).

The research firm expects the U.S. mobile ad market to grow 96 percent in 2012, which is a decline from the 126 percent growth in 2011, but Frederickson said they expect growth to slow because the market is maturing.

Despite the booming interest in mobile advertising, it’s important to note that mobile advertising still accounts for just one percent of the total ad spend in the U.S. and worldwide.

In terms of global ad spending across all categories, eMarketer projects that total media ad spending will grow 7.4 percent this year to $542.3 billion, with help from a small bump from the Olympics, and decline next year to 6.4 percent. Next year, ad spending in China will reach $53 billion, surpassing spending in Japan for the first time, and placing it behind the U.S. as the country with the second highest amount of ad spending.