With more Americans picking up the latest smartphones, advertisers are pouring money into mobile ads.

Mobile advertising has reached the mainstream of digital advertising in 2010, According to U.S. ad spending estimates by eMarketer.

By the end of 2010, mobile ad spending will have grown 79 percent or reached $743 million, eMarketer forecasts.

Anticipating slower growth in mobile ad spending in 2011, eMarketer is still predicting impressive double-digit rates. Mobile ad spending is expected to hit $1.1 billion in 2011 and $2.5 billion by 2014

“The expansion of the smartphone market and the attractive usage and demographic profile of smartphone owners have forced more marketers to pay closer attention to mobile,” said Noah Elkin, eMarketer senior analyst and author of the forthcoming report “Mobile Advertising and Marketing: Moving Past the Tipping Point.”