Both candidates have set up elaborate Web sites to explain policy positions, sign up volunteers, test new themes and collect donations, and both Kerry and Bush mentioned those Web sites during their convention speeches.
But neither has spent much effort trying to reach out to Internet users who don't visit http://www.georgewbush.com or http://www.johnkerry.com, the nonprofit Pew Internet and American Life Project found.
Kerry has raised more than $80 million of his $233.5 million from 500,000 online donors, according to campaign officials. Bush officials have not disclosed how much of the $242 million they have raised came through the Internet.
Both candidates and their parties have spent $2.7 million on online advertising, the nonpartisan group said in a report. That's less than half the $5.7 million Kerry raised through the Internet the day he accepted the Democratic nomination in July.
Together, the two campaigns have spent $100 on television ads for every $1 they've spent online, the study found, and many of those online advertising dollars were spent trying to elicit more campaign contributions.
The Kerry campaign spent $1.3 million in online advertising between January and August, compared with $419,000 by Bush. The Republican National Committee spent $487,000 during the same period, while the Democratic National Committee spent $257,000, according to the report.
Independent advocacy groups have spent a total of $184,000 online, with $104,000 of that being spent by the liberal MoveOn.org Voter Fund, the study found. Swift Boat Veterans for Truth, which spent heavily on television ads attacking Kerry, spent no money on online advertising.
The report's author said both campaigns were missing an opportunity to reach undecided Internet users.
"Online advertising could be a good way for campaigns to get the attention of the tens of millions of eligible voters who use the Internet but have yet to visit a campaign Web site," said Michael Cornfield, a senior research consultant with the Pew group.
Both campaigns favored local media sites for their online ads. The Bush campaign advertised most heavily on the Web site of a Fox TV station in Portland, Ore., while Kerry spent most at the Web site of The San Francisco Chronicle.
The advertising data was collected by Evaliant Media Resources, which used automated software to determine what sort of advertising was on Web sites. The company archived political ads for analysis and estimated how much money was spent placing them.