I visited that link for the first time. Had to go through the intro page with the two big green buttons. Chose the "search history" button (not the All Web, wit

I visited that link for the first time. Had to go through the intro page with the two big green buttons. Chose the "search history" button (not the All Web, with toolbar). My history page was completely empty. Then I tested one search (in another window). Refresh history page, there it is. So it was off before, clicking the button had turned it on. I deleted that history item, then clicked the "pause" link on the side-list. Was informed that no history would be collected until I clicked "resume". TL;DR: if going in for the first time, hitting a button on that page will start collecting search history. Apparently.