[Nextgrid]

> spyware, adware

Most advertising behaves like spyware for targeting purposes. It would be fine if it was consensual, but it's basically never the case.

> scareware

This is more about the ad's content than the concept of advertising itself, but online advertising is essentially the wild west and advertising platforms happen to get away with serving misleading ads that use scare tactics to get the user to do something against their best interests (sometimes even downloading actual malware).