Final answer:
Software that generates unsolicited targeted pop-up advertisements based on a user's browsing history is known as Adware. It is considered less harmful than spyware or ransomware but can still be a significant nuisance by tracking online activity for advertising purposes.
Step-by-step explanation:
Software that collects a user's web browsing history to create unsolicited targeted pop-up advertisements is called Adware. Adware is a form of software that can do more than just display advertisements; it can also track a user's online activity and personal information to target specific types of advertisements towards the user. While adware can be a nuisance, it is usually not as harmful as other types of unwanted software like spyware, which secretly gathers user information without consent, or ransomware, which locks users out of their systems until a ransom is paid.