Technology News Firefox unveils a new add on to know who is spying on users

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 move comes the same week that Google pushed ahead with its controversial new privacy policy, built to provide even more data for Google's $28 billion advertising business - despite concerns that the harvesting of private data might be illegal in many countries.

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.

Google's new privacy policy allows it to "streamline" data from Android phones, YouTube, Gmail and web browsing to target its adverts even more precisely towards individual web users.