Google is to give more weight to pages that display content above the fold, rather than filling that top space with adverts:
In our ongoing effort to help you find more high-quality websites in search results, today we’re launching an algorithmic change that looks at the layout of a webpage and the amount of content you see on the page once you click on a result.
As we’ve mentioned previously, we’ve heard complaints from users that if they click on a result and it’s difficult to find the actual content, they aren’t happy with the experience. Rather than scrolling down the page past a slew of ads, users want to see content right away. So sites that don’t have much content “above-the-fold” can be affected by this change. If you click on a website and the part of the website you see first either doesn’t have a lot of visible content above-the-fold or dedicates a large fraction of the site’s initial screen real estate to ads, that’s not a very good user experience. Such sites may not rank as highly going forward….