Wow, great link. This is just what I've been looking for. One does wonder how much of it is expectation effect. I mean if I didn't know the Benny Hill tune and it was labelled "focus" would it still work?
At a point mid-summer, the effectiveness wore down for a while - I even asked Aaron (one of the founders, but also available via their little support window in the corner) about adding new tracks to Focus, which I'm sure others had also requested, because they added a bunch of new tracks and it became even more effective than before. They also seem to have removed some of the tracks that weren't very effective.