Sgt_Kickaxe - I sense we have similar observations , even though you are able to be specific.
My hunch is that if we look at factors like the one you are describing , more science may come into the discussions.
Again , these early observations taste of the relevance signals that may have been tweaked. Why would Google want Ebay determining what results can appear when it prefers to control the output itself. More Adwords revenue benefit maybe with higher click thru's .
Never loose site of the commercial benefit that drives Google in it's search for more revenue by controlling the funnel.