What are these Antimalware Doctor all about

There are lots of pop ups telling me to the buy the full version. What's this?

Antimalware Doctor is a dangerous fake anti spyware programs to hit the internet. Antimalware Doctor will try and trick you into buying the full version by using scare tactics. It will bombard you with fake pop-ups and security alerts. It will also run fake scans and try and get you to buy the full version by giving false alerts. It goes without saying that you should not purchase the full version.
REMOVE THEM!