There are early reports at WebmasterWorld that search engine results for queries specifically three words long, have been fluctuating. Here are some quotes...
Solid at position 4 or 5 for 4 months, this morning bouncing around 11,12,16
On yahoo.com I jumped from 4 to 2 today.
Yes, Yahoo page count for my main site is jumping a lot at the moment. Worth keeping an eye on.
Forum discussion at WebmasterWorld.

Comments:
c
09/13/2005 08:01 pm
I have noticed that yahoo was jumpy, however I think they are targeting search based on cookie. eg. One of my sites I thought "disapeared".. from #4 position to page #4. However my stats showed an increase in traffic from yahoo. I use firefox and decided to open ms explorer and try the same search, and I am #2 on the first page.