When Google Panda algorithm update came in, there were several notions about the above the fold concept. If there is less content above the fold Google will penalize such sites now onwards. Such sites may lose ranking in SERP's. If you click any link to the website and you see the page plastered with promotions and banners it can be annoying to users and leads to poor user experience. This is yet another Google's effort to provide better search results quality.
Matt Cutts of the official webmaster blog said that this algorithmic change won't affect those sites that display ads to normal degree. But going too far can lead to penalty. But in my opinion ads should never be the part of your main content. One should put them in side banners so that you are not annoying your users.
Google recommends using browser size tool to see how your website would look under different screen resolutions. You can also know about above the fold tool.
It would be interesting to know if Google penalize itself or follow their own algorithm update. Most of the times Google displays "sponsored links" in the search queries. Though they may say user might be interested in those links but I guess it is not always so. See the image below.
It would be interesting to know if Google penalize itself or follow their own algorithm update. Most of the times Google displays "sponsored links" in the search queries. Though they may say user might be interested in those links but I guess it is not always so. See the image below.