A Rogue Program is a program that pretends to be a legitimate programs, but instead displays false information in order to trick or scare you into purchasing it. Most Rogue programs state that they are legitimate applications, but are typically clones of other lackluster products repackaged under new names and graphics. Most Rogue programs also use highly aggressive sales tactics which include adware, Trojans that display fake security alerts, or claims that they have won awards from major publications and companies. What it all boils down to, though, is that these types of programs are either deliberately deceptive or displaying numerous false positives in order to convince you to purchase their software. This is because the single most important thing to the creators of Rogue software, is to sell as many copies as they can. That means that the people, or affiliates, who are selling this software can do so by any means. This ultimately leads to deceptive advertising and the use of malware to sell the software.
A common approach by Rogue programs is to display either fake results or exaggerated results when the program scans your computer. When the scan is finished you will be shown a list of legitimate files and Windows Registry keys that are flagged as security threats. In some cases, the Rogue programs actually create the files and Windows Registry keys on your computer so that they can be detected as malware. Then in order to remove these threats, you must first purchase a license of the software. These fraudulent tactics are used to scare you purchasing this software. Now it should be noted that there is nothing wrong with a program requiring you to purchase it before it will remove any infections. It is wrong, though, to display false information to scare you into doing it.
Another common tactic used by Rogues is to advertise, or even directly install itself, through the use of malware. Rogues programs are typically introduced into your computer when a person visits pornographic or sites that offer copyrighted content. In some cases you will be infected by just visiting these site, depending on what security updates are installed, and in other cases you must first run an executable. Either way, your computer will have malware installed that displays fake security alerts stating that you have some security risk and must install a piece of software, the Rogue, to remove it.