Does Y! Use HillTop?

Anyone else seeing this?

[Buddha]

I have 2 sites that keep switching places for the #1 SERP. ie. day 1, site 1 ranks, day 2, site 2 takes over. I've never seen this before in Yahoo and I follow it pretty closely. I have seen this happen in G a yr or 2 ago. Both sites are in the same industry but have different content, are not linked to eachother, and are on different IPs. The only footprint that may be similar is their link partners.

Anyone else notice something similar to your sites?

[martinibuster]

Bumpity bump.

[Buddha]

Actually, I don't think Y is that smart. I think they are using 2 indexes or sets of results.

[internetheaven]

I would agree with the 2 indexes theory but from a different evidentiary point - the number of pages of each of my sites changes constantly but always switches between two numbers.

This is a clever method for many reasons but the most prevalent to me is the "testing" abilities. Once the index has been updated they slowly turn up the frequency it is used whilst they deal with problems that have occured with it.