The company, Adtech, found that during October and November, only 0.11 percent ofusers ever clicked on an ad, compared with around 0.5 percent of IE users. The percentage of IE users clicking on ads varied depending on which version of the browser was being used, the company said: from 0.44 percent of version 6.x users to 0.53 percent of version 5.5 users. The survey was based on 1,000 Web sites in Europe that use Adtech's ad server.
Dirk Freytag, the chief operations officer of Adtech, said in a statement that the reason for this trend is probably the different surfing habits of Firefox and IE users, plus the inclusion of an integrated pop-up ad blocker in Firefox. Among IE users, only those who have version 6 and who have installed Windows XP Service Pack 2, although IE users can also choose to install a third-party pop-up blocker.
David Hallowell, a Mozilla contributor, said this trend may have emerged because nontechnical Web surfers, who tend to be IE users, are more likely to click on pop-up ads by mistake, because they think the ad is a system dialog box.
"People click on (pop-up) ads because they think the system's trying to tell them something," Hallowell said. "The average Firefox user is more aware that they're ads, not system dialogs."
Hallowell added that Firefox users may be more likely to click on targeted ads, rather than other types. "Most people I know are more happy with Google's targeted ads--they don't like big banner ads that are totally unrelated to what they're looking for," Hallowell said.
Adtech's findings could have significant implications for the online-advertising market. It may be bad news for sites that rely on online advertising, because as the number of Firefox users grows, those sites may get lower click-through rates. Alternatively, if Hallowell's theory is correct, then click-throughs from Firefox users could actually be more valuable--if a Firefox user is considered more likely to have intentionally clicked on an advertisement.
In some cases, Web surfers would be well-advised to stay clear of banner ads. Last month, ZDNet UK reported thatand have modified the banner ads so that they redirect users to Web sites that download malicious code.
Ingrid Marson of ZDNet UK reported from London.