Scareware:

Rogue Scanners/Rogue Antivirus:

What is a Rogue Scanner?

• Rogue scanners masquerade as antivirus, antispyware, or other security software, claiming the user's system is infected in order to trick them into paying for a full version.
  
• Rogue scanners are often advertised as a free antivirus download or free online scan.
  
• Rogue scanner typically displays false virus alerts, with instructions to buy the "full version" in order to remove the fictional infections.

Usual ways of delivery:

• Email scams disguised as greeting cards or breaking news alerts;
• Advertisements that offer a free scan or system tune-up;
• Compromised websites retrofitted to exploit software vulnerabilities.

Symptom of a rogue scanner:

• Unexpected virus alerts from a product you don't recall installing

Examples

• Advanced Antivirus
  [o] False virus alert
  [o[ Pay for removal
  [o[ Price given $49 may be highly inflated on credit card $190 or more.
  
  System Antivirus 2008

Method of Infection:

• Exploit security vulnerabilities to forcibly install.
• May attempt to trick users into installing a free security scan or system tune-up.
• Email scams: breaking news alert

Just some highlights here- but any time you're not sure, don't!

Rogue Anti-Spyware list: http://www.spywarewarrior.com/rogue_anti-spyware.htm
Newest Rogue Threats Forum: http://malwarebytes.org/forums/index.php?showforum=30
Wikipedia Rogue security software: http://en.wikipedia.org/wiki/Rogue_software

I wonder if this could / should be "pinned"

Thanks for adding kimsland. My thought was to give a broad overview of 'scareware' in the hope that users will recognize what it is.

B00kWyrm, getting "pinned" is kind of a double-edged sword. I am finding that most of the users 'don't' see or read the pinned threads-but-it gives us a good reference to draw their attention to. Unfortunately though, the attention would likely be after the fact most of the time.