Yesterday WebmasterWorld featured a thread in the supporters forum named Google Update?. Later last night, Phil Craven started a thread at Search Engine Watch Forums named Significant Changes In Google Results: March 2005 which Danny Sullivan featured and then included in his What's Going On With Google? sticky.
Basically what is being reported is that Google has 64 data centers, of those data centers, Phil noted a grouping of the same results in three. So Group A had ~22 data centers that all had the same results, Group B had ~22 data centers that all had the same results but different then A or C, and Group C had ~22 data centers that all had the same results but different then A or B.
What Phil reported was that two of those groups consolidated, so Group C not has the same results at Group A. And now we have two groups instead of three.