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.