Lately Google has brought the Google Caffeine update from the sandbox into the main search results.
While in the sandbox, the caffeine update rarely effected rankings. It was more about the speed of which the results would get returned and the number of pages that it would return.
Since this update has made its way into main search about the only thing noticeable is when looking at the number of pages indexed through doing a site:example.com search. This has stepped up across a number of sites. Seeing jumps in pages returned like:
Before this update, combining the number of pages indexed to the amount of search engine reach. This gave a quick overview of how well indexed a site is. When dealing with a large site this is critical.