Spyware and Advertising
Advertising is a fact of life on the Internet. Many websites display advertising-- as do many spyware. Some programs simply display pop-up ads on a regular basis. Others display ads in response to specific sites that the user visits. Spyware operators present this feature as desirable to advertisers, who may buy ad placement in pop-ups displayed when the user visits a particular site. It is also one of the purposes for which spyware programs gather information on user behavior. Pop-ups are one of users' most common complaints about spyware.
Many users complain about irritating or offensive advertisements as well. As with many banner ads, many spyware advertisements use animation or flickering banners which can be visually distracting and annoying to users. Pop-up ads for pornography often display indiscriminately and could possibly violate anti-pornography laws in some jurisdictions.