Matt Cutts has been telling us that there is a test data center out there where Google is testing future algorithms. There is supposedly a special Googlebot named "Mozilla Googlebot" that is out there crawling pages for this special index. Dayo_UK created a WebmasterWorld thread named Mozilla Googlebot and the New Index at 126.96.36.199 where he describes that the index at 188.8.131.52 is "being built for the future." The pages in this index seem to have cache dates in November time frame, which may be consistent with Matt Cutts comment; "the test data center certainly has some different crawling and indexing characteristics."
What is important, for you SEOs, is that this data center should roll out in "months." So it is nice to be prepared for it.
Forum discussion at WebmasterWorld.