Revenue earned by Bloggers from the Google Adsense program is under threat following reports that the latest security patch for Microsoft Internet Explorer (IE) blocks the display of Adsense advertising when IE is set to a “high” security setting.

Although Mozilla Firefox is taking market share from the once dominant IE, IE still remains the dominant browser on the internet, although less so amongst blogs, some of whom are now reporting an even split between those using IE and Firefox.

It should be noted that the number of IE users with their security settings set to high is not known, and the number of users regularly installing security patches is still below 50%.

None the less, even if 10% of readers are blocked from seeing Adsense advertising, the collective value to the blogosphere, given the scope, prevalence and success of the program, could well cost bloggers worldwide millions of dollars in lost revenue in the coming months.