SEOmoz has put together a small chart analyzing the top 20 results for two searches at Google, one a normal 2-word phrase, and the other with much discussed -asdf filter (done by appending 15 -asdf onto the back of the query). The two unique results sets have been analyzed using every known method of SEO measurement, including links, theme, age, etc.

In the future, we hope to be able to add more searches onto the chart, but the analysis is very time-consuming. See the current page - chart of Google's -asdf filter.