bsterz - 3:34 pm on Mar 1, 2013 (gmt 0)
Gyppo - I have been seeing similar behavior for a while now, maybe 3-6 months. The changes are not always extreme, but there are very few stable results. I have wondered if search query volume is one of the many triggers. Such as, after a keyword has been searched x number of times the SERPS are reordered. This could be learning.