Google update I see...

With website going up down and everywhere in the google serps I am positive that there has been a very recent google update this December. Website that were ontop are now gone and website that I have not even seen before for some keyword that I watch are now hitting page 1.. Very odd indeed but I think spam website are slipping more and more through.. well spam pages that are on high authority websites... like YouTube and spammers selling stuff on amazon and ebay which then spam the urls. So it seems as though spammers mayn't be able to start spam website from scratch anymore or subdomains on free web 2.0 sites but they can still rank super well if they are on one of these super website that always dominate.