they have been around much longer than a few months. at the very least since the mid 90's, me personally I have had on my own PC's and some of my friends or co-workers since Windows 95.
(Since the internet started to be popular).
we all know that a lot of this come form porn sites (some of them masquerading themselves as legit sites) but some are somehow from legit sites. (or somehow find a way to appear legitimate).
keeping your antivirus and antispyware up to date is the best that anyone can do, also stay away from known spyware sources and simply do not click on any pop up windows that are trying "to help you", they are always the problem, and once you click on them, well, your toast.