That part also jumped out to me, but made me worry that the author isn't accounting for novelty effects. When you make something weird at first it does well, an

That part also jumped out to me, but made me worry that the author isn't accounting for novelty effects. When you make something weird at first it does well, and then later as people get used to it the lift goes away or even turns negative. With a lead gen funnel, where everyone is going through for the first time, this is much less of an issue than a site with long term users. In the latter case you want to measure learning effects, while in the former no individual is in a position to learn. Novelty could still wear off in lead gen, though, as companies copy each other and your weird new pattern starts to show up elsewhere and become familiar.