Final answer:
Adware is the type of software that delivers unexpected and unwanted advertising content, often bundled with other free software.
Step-by-step explanation:
The type of software program that delivers advertising content in a manner that is unexpected and unwanted by the user, typically included in malware, is known as adware. Adware can display ads on your computer, redirect search requests to advertising websites, and collect marketing-type data about you (such as the types of sites that you visit) to tailor future ads to your interests. Unlike a keylogger, which records keys pressed on a keyboard; spam, which is unwanted email; and a trojan, which is malware that is disguised as legitimate software, adware specifically pertains to software designed to display advertisements and often comes bundled with other free software.