Cydoor Desktop Media is an Israeli online advertising company. Cydoor originally placed ads only in software programs such as Kazaa, but has now expanded into running ads on websites as an advertising network.
Because of Cydoor's highly controversial practices of running ads in software programs, Cydoor has been associated with spyware - and many Anti-Spyware and Antivirus applications will flag the software as such.
It used to be that a user could uninstall Cydoor and continue to use the program it came with, but that is sometimes no longer the case. Now Cydoor is treated as a vital piece of software code by the parent program, and removal may cause the program to stop working. The website's FAQ explains, "Our components...are the main revenue generating components for our software partners," as the way of explaining their supposed necessity. The program has been known to cause problems in Windows, but the company asserts that this is due to an old and buggy version of the software. They also claim not to harvest personal information unless "the user voluntarily supplied it".