Matt Cutts has revealed at the recent Pub Con in Las Vegas that Google will soon be rolling out a new part of their search engine results. When it comes to long tail queries, in the shopping niche for example, Google could return quite a few results from a single site. Lots of sub domains and folders from one site could appear on a single page.

For those not familiar with the techno babble that is "long tail queries", a long tail query is a search request that is very specific. Such as "small green glass world war 2 figurine". It would normally only return a few, very specific results in the SERPS. This is in contrast to a short tail query that is very generic and can return many results that may not be entirely what you are looking for.

To help with diversity, Google hopes that now, only a couple of results from 1 site will appear. This is to help with the general diversity of their search results, but if some pages are extremely relevant, then they may still appear on one page. Very specific search terms like "Google" however will still return mostly results from Google.