[ronack]

This is interesting but I definitely question some of the results, for instance reporting a negative impact for changing search results. Many businesses have been built on improving conversion through search result optimization.

[robbiemitchell]

I interpreted this as them creating/improving on-site search. Not related to adwords or display optimization.

[ronack]

Sure, but what were the improvements to on-site search? More relevant results? Tweaking the display? I know from experience that improving search result relevance in e-commerce has a (sometimes drastic) improvement in conversion.