Firefox is working to keep advertisers from eavesdropping on its users' Web-browsing experience (thanks, Mozilla!) by blocking third-party cookies, using a patch developed by Jonathan Mayer, a grad student at Stanford. The current Firefox already offers manual blocking, but by Firefox 22 (19 came out a few days ago), it will be the default setting on this popular browser.

The move blindsided advertisers — Mike Zaneis, the Internet Advertising Bureau's senior vice president, tweeted that the default block on cookies "would be a nuclear first strike" against the ad industry, which often targets ads according to the pages a user visits. Firefox is really just following the example of Apple's Safari, which does not allow third-party cookies, using a more relaxed version of the Firefox policy. Internet Explorer enables most cookies and Chrome has no restrictions.

Mayer assured users that while some sites' codes may need to be tweaked to accommodate the patch, Firefox will be closely monitoring the policy before its release in early April. "The patch will spend about 6 weeks each in the pre-alpha, alpha, and beta builds," he wrote, encouraging users to report any problems to Mozilla support.

The new policy would not clear cookies from any current versions of Firefox, so if you plan to use version 22 to its full potential, clear your cookies once it's been installed, Mayer warned.

The Federal Trade Commission requested a mechanism to block online tracking, at which point Mozilla offered its Do Not Track (DNT) technology, reports CNET. The initiative stalled over disagreements on how to standardize it. Advertisers said they would acknowledge a DNT setting if users enabled it specifically, but would ignore it if it were the default.

Some users said they would rather keep the tracking on, stating that they preferred targeted ads that are relevant to their interests over random ones. Other users prefer blocking ad cookies entirely, the idea of losing privacy at all being abhorrent to them.

Which would you prefer?