Maybe you already follow the webmaster videos from Googles Matt Cutts in which he answers questions from webmasters. Matt is doing this for several years now and which I think is a good thing. There are a few hundred videos now and he even answered one of my questions once :-).
In his latest video Matt answers a question from himself. “Does Google take manual action on webspam? Does manual action result in a removal or can it also be a demotion? Are there other situations where Google will remove content from its search results?”
The answer to this is in short, Yes, Google will take action when the company sees violations of the guidelines, this can be a demotion but it tends to be removal. More in the video below.
You can watch all other videos on the Google Webmaster channel on YouTube.