Following Google's preview release of the Caffeine Update yesterday, the most recent tweak of their famous search indexing and ranking algorithm, here's a video interview of Google's Matt Cutts from WebProNews.
Bottom line: Caffeine mostly consists of under the hood tweaks that allow for faster and more robust indexing of documents, possibly laying the groundwork for a move towards real-time search results, better semantic content interpretation, and universal search.
Rafe Needleman over at CNet also gives a pretty good roundup of Caffeine. In his exploration, news results seem to appear more prominently.
Check out Google Caffeine and let me know what differences have you noticed?