Gator, a type of adware that offers free use of an application if users agree to view a series of pop-up messages tops the list of spyware most frequently detected by PandaLabs in 2006. Some versions of this spyware replace banners on web pages visited with those created by the malicious code itself. Second and third place in the top 10 are occupied by Wupd and Ncase respectively. Both offer free use of an application in exchange for displaying advertising messages.
They also monitor users' Internet movements and gather data about habits and preferences. This information is then used to personalize the advertising displayed. Additionally, Ncase changes the Internet Explorer home page, as well as the default search options. The adware CWS came in fourth place. This can be installed without a user's consent or without them being fully aware of the functionality of the tool.