page segmentationPhoto by: 0olong
From it’s research papers here

A new web content structure analysis based on visual representation is proposed in this paper. Many web applications such as information retrieval, information extraction and automatic page adaptation can benefit from this structure. This paper presents an automatic top-down, tag-tree independent approach to detect web content structure. It simulates how a user understands web layout structure based on his visual perception. Comparing to other existing techniques, our approach is independent to underlying documentation representation such as HTML and works well even when the HTML structure is far different from layout structure. Experiments show satisfactory results.

A visual graphic could be found on MadHat’s site!

So, how could one use it in SEO?
Ever thought why contextual links was wighted more than non-contextual links. Well this is the reason which explains, why the contextual links are so effective. A search engine could define an algorithm that divides the page in blocks, giving priority to the part which has content. If a link is found with in the content then, it is supposed to be of some importance and given more value. Now, look the block which is on the sidebar, this has links to so many sites (advertisers, paid links) with little or no text. This is given low weight. I wonder where else could they use this algorithm.