NEW YORK: Mobile adspend in the US rose by 35% to $648 million (€483m; £441m) last year says eMarketer, the research company, which predicts the medium will expand by a further 17.9% in 2009 to $760m.

The company argues that 2008 was a "turning point" for mobile advertising in America, largely due to the introduction of "smartphones", and particularly Apple's iPhone, which has led to better connection speeds and increased use of the mobile web.

As a result of "heightened activity and interest," eMarketer estimates that the medium will grow by 30.9% to $995m in 2010, by 41.7% to $1.4bn in 2011, and then by 69.5% to $2.3bn in 2012.

Overall, ad revenues through the channel are set to reach $3.3bn by 2013.

By contrast, eMarketer has revised down its expectations for online adspend this year, and now predicts it will grow from a value of $23.4bn last year to $24.5bn in 2009.

The medium's expansion is then expected to accelerate each year after that until the medium takes an overall total of $37.2bn by 2013.

Data sourced from eMarketer; additional content by WARC staff