Term coined by McAfee for a type of software program that may be unwanted, despite the possibility that users are consented to download it. PUPs include (most commonly) adware, spyware and dialers. Some files from these programs will download taskbars.
Most common category of PUPs is rogue software, in which a program bribes the user to pay for a "removal" of non-existent malware on his/her computer.
PC Optimizer Pro is a good example of a potentially unwanted program