Retailers will increase their spending on online video marketing campaigns at an annual growth rate of 73 percent over the next several years, according to a Forrester Research study. Spending by retailers on online video marketing will reach $338 million this year, up from $158 million in 2007, then continue growing to $2.32 billion by 2012, said the report, titled, "Retail Interactive Marketing Grows Steadily," by analyst, Shar VanBoskirk.

By comparison, other more traditional forms of online advertising will continue to dominate even while growing at a slower rate, the study said. Online display ads will grow at a compound annual growth rate of 20 percent from 2007 to 2012, growing from $2.07 billion last year to $2.78 billion this year, and just under $5 billion by 2012.

Search engine marketing will grow at a compound annual growth rate of 24 percent over the same period, from $2.82 billion in 2007 to $3.63 billion this year, and $8.27 billion by 2012, according to the Forrester report.