I came across this pretty neat site that compares search terms across two search engines, Yahoo and Google.
Enter a search term and the row of dots indicate the order in which results appear (e.g. the far left result is the first result for each search engine). The blue dots are results which occur in both Yahoo and Google, and they have a blue line connecting the matching results. This is a away to visually see whether Google and Yahoo have similar rankings for pages on a topic.