Do Not Track. Many users think that not only applies to preventing a person sharing your machine from trying to peek at the websites you visited but also to blocking views to outside trackers. Most major browsers present a "Do Not Track" option, but not all companies honor it.

"Tracking," said the Mozilla support page, "is the collection of a person's browsing data across multiple sites, usually via included content. Tracking domains attempt to uniquely identify a person through the use of cookies or other technologies such as fingerprinting."

"All major browsers offer some form of experience that is labeled 'private' but this is typically intended to solve the 'local' privacy case, namely preventing others on a shared computer from seeing traces of your online activity," said the Mozilla blog, announcing their work. "This is a useful solution for many users, but we're experimenting with ways to offer you even more control when they open Private windows."

Mozilla's team in looking for a better solution is offering a Private Browsing feature in pre-beta. Mozilla said on Friday that it is experimenting with new features in pre-beta versions in Firefox Developer Edition on Windows, Mac and Linux and Firefox Aurora on Android.

The new tool in pre-beta builds of Firefox could help block browser tracking across sites.

Zach Miners, who covers search for IDG News Service, reported that Mozilla wants to make private browsing truly private. The block, he said, would affect outside parties such as "ad networks or analytics companies" tracking users through cookies and browser fingerprinting.

The Mozilla blog said, "The experimental Private Browsing enhancements ready for testing today actively block website elements that could be used to record user behavior across sites. This includes elements like content, analytics, social and other services that might be collecting data without your knowledge."

Users, though, can unblock specific websites if they wish. Why would they do this? The blog said, "In some cases, websites might appear broken when elements that track behavior are blocked," while unblocking these would enable one to view the website normally.

"New Experimental Private Browsing and Add-ons Features Ready for Pre-Beta Testing in Firefox" was the title of the blog announcement on August 14. The Electronic Frontier Foundation, meanwhile, has turned its attention to a new standard for the "Do Not Track" browser setting. The IDG News Service earlier this month reported that a group led by the Electronic Frontier Foundation is looking to make that a more meaningful action.

"The EFF and others have published a standard policy it hopes advertisers, analytics companies and publishers will adopt in order to respect the wishes of users who don't want to be tracked online."

As for the pre-beta, Mozilla has asked the testers for feedback to make the experience better for future releases. They have a feedback page for users of the "experimental Private Browsing."

Commented Lee Mathews in Geek.com: "Mozilla's making the assumption (a safe one) that if you've consciously clicked in to a private window that you really, really want your privacy respected."

Mozilla's solution still has a way to go in the development process but, said Mathews, between the approach on the part of Mozilla and the thinking coming from the EFF, "maybe someone will finally come up with a system that works." A workable system amenable to both user and business sides would respect people's privacy wishes but allow publishers to display revenue-generating ads that keep their sites running.