• by Mark Walsh  @markfwal, September 9, 2008

With national polls Monday showing John McCain pushing ahead in the presidential race, a new study says search marketing could play a key role in influencing all-important swing voters.

About 7% of people searching online said they were likely to change their vote before the election, according to a survey by search engine marketing firm Didit that looks at the interplay of search activity and political attitudes.

"As we near Election Day with a remarkably even presidential race, an enthusiastic and interested population will turn to search engines for as much information as possible," said Didit President David Pasternack, in a statement.

What's more, there's no limit on how much any individual or political action committee can spend on search terms and no record of who is buying the ads. "It's a little like the Wild West," said Didit co-founder and CEO Kevin Lee. "Only the search engines know what dollars are being spent by whom."

In monthly reports filed with the Federal Election Commission, the Obama campaign has disclosed payments to major search providers including Google, Yahoo and Microsoft. Obama has already spent more than $3 million this year with Google alone.

The McCain campaign doesn't break out spending by online vendor in its FEC reports, but the Republican nominee is believed to be spending millions on a search campaign viewed as more aggressive and effective than Obama's.

Data released Monday by Nielsen Online showed McCain ramping up both display and search advertising in August. Image-based impressions jumped 254% during the month to 58.3 million, while sponsored search link impressions increased 43% to 21.6 million.

By contrast, Obama's display impressions dropped by almost half to 216 million as search impressions fell by 18% to 949,000--less than 5% of McCain's total.

In addition to sheer volume, some search experts say the McCain campaign has shown more savvy in using paid search by buying keywords tied to election issues and outbidding the Obama campaign on terms such as "Joe Biden."

Snapping up keywords linked to issues or opponents' names could provide an edge--especially with voters who can still be swayed, according to Janel Landis, senior director of search development and strategy at search marketing firm SendTec.

"What the Obama/Biden camp refers to as the "scare tactics" of the McCain campaign are seamlessly integrated between offline and online, hitting the undecided voters from all angles with consistent messaging," she wrote in a report as part of its ongoing analysis of the candidates' online campaigns.

When "Sarah Palin" emerged as one of the most-searched terms on the Web last week, the McCain campaign was ready with ads that invited users to learn more about the Republican vice presidential pick.

Not only did the Obama campaign not bid on her name, but also passed on related terms such as "Alaska State Trooper" and "Palin Allegations" that could link to information about Palin pushing to have her former brother-in-law fired as a state trooper.

The report noted that even the company Zagg, which makes a protective sheath for cell phones and other gadgets, bid on "Sarah Palin" to run an ad claiming "invisibleSHIELD for the iPhone 3G would make the perfect running mate."

The Didit study suggests that search advertising is an effective way to sway potential swing voters. It found that the people most likely to change their view of a candidate are those who click on links favoring the opposition, with 40% switching sides.

Nearly one-third switched based on negative search ads. "That's proof that attack ads work on the Internet, too," said Didit's Lee. The study further indicated, however, that opposition-related keywords had only a slight effect on changing voters' opinions, while ads praising the candidates were the most persuasive.

The Didit survey, accessed via a sponsored link, was completed by 1,447 participants, more than 95% of who are already registered to vote in the upcoming election.