This threat is a sub-category of the Spyware classification. Most adware installations are not malicious and are not difficult to remove. Some adware are installed in a way that makes them tricky to remove due to modifications such as browser helper object assignments, and uncommon system registration. Adware commonly targets users by communicating with a web server and sending browsing habit data in an effort to deliver to the targeted user advertisements that are similar to items viewed on various web sites. Adware is most often a profit generator for the company connected with the adware installation.