U.S. advertisers consider their own Web sites to be the most effective online marketing tool, according to the “Annual Ad Spending Study” by Outsell Inc. E-mail and search marketing came in second and third.

The study showed the over 1,000 U.S. advertisers surveyed spent about 12 percent of the total 2007 advertising budgets on their own Web sites. Outsell also found that the advertising budget for search are slated to grow by 40 percent on average this year, but “small, medium, and large companies exhibit major differences in where they allocate their budgets and what strategies they find most effective,” said Leigh Watson Healy, Outsell's chief analyst.

For example, 58 and 32 percent of small firms with less than 100 employees ranked it effective for Google's and Yahoo's keyword research, respectively. For medium-sized firms with 100 to 1,000 employees, 75 and about 50 percent rated Google and Yahoo! effective, respectively. However, 63 percent of large companies with more than 1,000 employees think Google and Yahoo are effective.

Outsell indicated the greatest opportunities for online publishers lies on the medium-sized advertisers, as they are estimated to spend 63 percent more on Web advertising this year, rather than merely 14 and 19 percent for small and large companies, respectively.