Web browsers generally allow users to send a "Do Not Track" signal that lets advertisers know the user prefers not to be tracked for the purposes of serving up personalized ads.

But it's largely a futile exercise, because websites and advertising networks are free to ignore the signal. Even Yahoo, which had been honoring Do Not Track requests, decided to stop doing so this week.

The Electronic Frontier Foundation may have a solution. Last night, the group announced "Privacy Badger," an extension for Chrome and Firefox "that analyzes sites to detect and disallow content that tracks you in an objectionable, non-consensual manner."

Privacy Badger doesn't automatically block ads. The group explained:

When you visit websites, your copy of Privacy Badger keeps note of the "third-party" domains that embed images, scripts and advertising in the pages you visit. If a third-party server appears to be tracking you without permission, by using uniquely identifying cookies to collect a record of the pages you visit across multiple sites, Privacy Badger will automatically disallow content from that third-party tracker. In some cases a third-party domain provides some important aspect of a page's functionality, such as embedded maps, images, or fonts. In those cases, Privacy Badger will allow connections to the third party but will screen out its tracking cookies.

Users who install Privacy Badger can whitelist websites. Additionally, "Advertisers and other third-party domains can unblock themselves in Privacy Badger by making a strong commitment to respect Do Not Track requests," the EFF said.

Privacy Badger works, but it's an "alpha" release so the EFF wants interested users to test it out before attempting to convince larger populations of people to install it. Privacy Badger can be installed on Chrome or Firefox here, and bugs can be reported on GitHub.

The EFF also helps maintain the HTTPS Everywhere extension, which attempts to force websites to encrypt communications with users who have the extension installed.