This is a really useful article from eConsultancy, highlighting the need to structure web pages to link through a hub/landing page, in order to concentrate search terms around a single page.
It uses the world cup as a case study to show how the Guardian got 1st page positions for the term, whilst the Mail came nowhere. The reason? The Mail kept adding pages in an ad-hoc fashion, so Google got confused as to which page it should prioritise for the term. In effect, whilst the Mail created lots of content, it canibalised itself by not linking all of the related content to one main hub page.
The case study is in-depth and features lots of data and graphs.