Update 2 Matt Cutts gave WebProNews another exclusive interview, in which he gave some more details about Caffeine among other things.

Its only hitting one data center before the holidays, and it isnt even live quite yet.Google will roll it out to more data centers in January. Update Out at PubCon in Las Vegas, Mike McDonald of WebProNews discussed the rolling out of the Caffeine update further with popular search enthusiast Barry Schwartz Original ArticleIt appears that the effects of Googles Caffeine update may be felt sooner rather than later. That is if you really do feel the effects at all.