Mozilla, the maker of Firefox, has unveiled a new add-on for the popular web browser that gives users an instant view of which companies are "watching" them as they browse, the Daily Mail reported on Friday.
The Collusion add-on will allow users to "pull back the curtain" on web advertising firms and other third parties that track people's online movements, says Mozilla CEO Gary Kovacs.
Google's business is built on advertising - the company earned $28 billion from its AdWords service in 2010.
Mozilla's Firefox is the world's second most popular web browser, a position under threat from Google's own Chrome browser. The Collusion add-on is an official Mozilla product, and was unveiled at the Technology, Entertainment and Design conference this week by Mozilla CEO Gary Kovacs.