A WebmasterWorld thread has some interesting conversation about an increase in long tail traffic people have been noticing from Google. Long tail traffic, if you don't know, are the longer more specific keyword searches, such as big blue pineapple chair searches, where the number of searches are very low but when they land on your page, the conversions should be high.
The reports seem to convey that when Google changed the way they handle supplemental index results just late last month, it actually is making an impact now. People feel that the supplemental index is truly not a separate index anymore and being treated as a listing in the main Google index would be treated.
Thus people are noticing large increases in those long tail referrals from Google, especially those with huge sites.
Which data centers at Google is this appearing on? It is hard to isolate, I am told, but here is one member's thoughts on that.
At the moment I am seeing the newer mixed results at most datacentres, earlier today when I was seeing the differences I was generally comparing the old results on 220.127.116.11 with the new 'mixed' results on 18.104.22.168.
Some feel that the supplemental index and main index are still separated but blended more, as Tedster and g1smd say, "this isn't a move out of Supplemental, but more a blending of results from both indexes."
This is awesome moderation by Tedster, he isolated this conversation and pulled it out from a different thread.
Forum discussion at WebmasterWorld.