TrackMeNot is a lightweight browser extension for Firefox that helps protect web searchers from surveillance and data-profiling by search engines. It does so not by means of concealment or encryption (i.e. covering one's tracks), but instead, paradoxically, by the opposite strategy: noise and obfuscation. With TrackMeNot, actual web searches, lost in a cloud of false leads, are essentially hidden in plain view. User-installed TrackMeNot works with the Firefox Browser and popular search engines (AOL, Yahoo!, Google, and Bing) and requires no 3rd-party servers or services.

TrackMeNot runs in Firefox as a low-priority background process that periodically issues randomized search-queries to popular search engines, e.g., AOL, Yahoo!, Google, and Bing. It hides users' actual search trails in a cloud of 'ghost' queries, significantly increasing the difficulty of aggregating such data into accurate or identifying user profiles. To better simulate user behavior TrackMeNot uses a dynamic query mechanism to 'evolve' each client (uniquely) over time, parsing the results of its searches for 'logical' future query terms with which to replace those already used.