E-mail marketing spending in the US will increase to $2 billion by 2014, which represents almost an 11% year-over-year growth rate, according to a new forecast report by Forrester Research. The report, called "US Email Marketing Forecast, 2009 to 2014," attributed the growth of e-mail marketing to falling CPMs (meaning that ESPs are charging less per e-mail), a higher return on investment, as well as the growth of social e-mail accounts. Because of this growth, in five years consumers will be hit with more than 9,000 e-mail marketing messages a year.