I know one thing- Google is having massive problems with "losing" websites, and a LOT of people are complaining. As a result of this as well as Yahoo's determined efforts to improve, Yahoo may again become the dominant force in the SE world.
Here's one small example. I have a site that was spidered by Googlebot, then was indexed and showed up in serps. Then it disappeared. Completely! Then it reappeared again...? All the while, it retained a solid position in Yahoo's DB.
I began to investigate and found this was happening to thousands of people as Google screws around with it's algo in real time. That SUCKS!
Also- it seems like AllTheWeb "linkpop" results have become useless. I've been finding that ANY iteration of the search phrase is showing up as a "link", whiuch is bogus. For example- if you search on "dogfood.com", they might find a reference to a sentence like, "your dog eats dog food. Commercially available....."
Then they will list that portion as a "link"! Net result, I've seen AllTheWeb "link" numbers have go through the roof.
I don't know what's happening over there. :-(