I just decided to look up string theory at mamma. I had a 'mouse twitch' (actually, because my thumb is busted and I'm being fragile with my left hand I didn't press shift even though I meant to) and didn't open a search result in a new window. Then I fumbled the Alt-tab keys and got a little lost, but I ended up finding the browser window that used to contain the search results.
When I clicked back, the item that had previously ranked first was ranked 4th. Interestingly, I hadn't clicked on the first item, I'd clicked on the second item.
I wonder if it was my choice of the second item (even though I was also going to click the first item, just for some reason I hadn't clicked it first) that caused the results to change..?
Anyway, it was interesting to see that.
...and now, hopefully, it will be interesting to read about string theory.