Advertisers are on track to spend $21.4 billion on the Internet in 2007, according to an eMarketer online ad spending report. By 2011 spending on advertisements online is estimated to hit $42 billion.

One major trend is that the nation's leading advertisers are moving more of their budgets from old media to the Internet. More than half of Advertising Age's "100 Leading National Advertisers" are decreasing their spending on traditional measured media and increasing the amount going to the Internet.

Search, display and classified ads in that order receive the largest share of Internet spending. Paid search's share of online ad spend will stay in the 40 percent range through 2011. Display ads will generate about 20 percent of Internet ad revenues through the rest of the decade. Classified ads will contribute about 17 percent.

The report says that Internet advertising will not be as much as projected. "Mainly because of the credit crunch and related economic fallout, Internet ad spending will not increase as much in 2007 and 2008 as analysts previously expected. However, reduced spending will be tempered by advertisers buying the low-cost display advertising gobbled up by mortgage companies' shrinking marketing budgets."

Online Ad Spending