"Do you shove lots of ads at the top of your web pages? Think again. Tired of doing a Google search and landing on these types of pages? Rejoice. Google has announced that it will penalize sites with pages that are top-heavy with ads."
It seems to me that Google is getting tougher with sites it sees as poor quality as it rolls out change after change to it's algorithm to encourage quality over quantity. Just like Panda which aims to kill off thin content and content farms, this new change will target sites that serve no other real purpose than to serve ads.
http://searchengineland.com/too-many...ut-algo-108613