The firm, Adtech AG, found that during October and November only 0.11 percent of Firefox users ever clicked on an ad, compared to around 0.5 percent of IE users. The percentage of IE users clicking on ads varied across different versions, with 0.53 percent of version 5.5 users and 0.44 percent of version 6.x users clicking on ads. The survey was based on 1,000 web sites across Europe which 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, and the inclusion of an integrated pop-up ad blocker in Firefox. Only IE6 users who have installed Windows XP SP2 have an integrated pop-up blocker, although IE users can also choose to install a third party pop-up blocker.
David Hallowell, a Mozilla contributor, said this trend could be because non-technical 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," said Hallowell. "The average Firefox user is more aware that they're ads, not system dialogs."
Another reason could be that Firefox users tend to be more likely to click on targeted ads rather than other types, said Hallowell. "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," said Hallowell.
Adtech's findings could have significant implications for the online advertising market. It may be bad news for sites which rely on online advertising because as the number of Firefox users grows, they 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 thought more likely to have intentionally clicked on an advert.
In some cases Web surfers would be well-advised to stay clear of banner ads. Last month ZDNet UK reported that hackers have attacked ad servers and have modified the banner ads so that they redirect users to Web sites that download malicious code.