Malware

There is also a class of advertising methods which are considered unethical and may even be illegal. These include external applications which alter system settings (such as a browser's home page), spawn pop-ups, and insert advertisements into non-affiliated webpages. Such applications are usually labelled as spyware or adware. They may mask their questionable activities by performing a simple service, such as displaying the weather or providing a search bar. These programs are designed to dupe the user, acting effectively as Trojan horses. These applications are commonly designed so as to be difficult to remove or uninstall. The ever-increasing audience of online users, many of whom are not computer-savvy, frequently lack the knowledge and technical ability to protect themselves from these programs.