I have a panorama of Montreal that I uploaded in October and was on page 2 or 3 for a search on 'Montreal'.
I sold it a few days ago and found it yesterday on page 1 (happy!) followed by my other images of Montreal.
But today it is gone and is nowhere to be found while my other images are still at the same place. The panorama appears only if I add another word to the search.
Is it another problem of cache or server ? I would understand if the image had came back to its previous position or if it was an image uploaded recently but it is not the case.
You can speculate all you want but you will never get a definitive answer on the exact working of the search algorithm. And also there is a thread Sean put up to let you know that what you see is not going to be the same as hat someone else may see. I guess you may get a boost in the search right after a sale and then other factors come in to play. Be happy you made a sale and that you were high ranked for a little bit. Also remember there is a search sort by "recently sold",so you might want to try that and feel a little better about how you rank.