The process he is describing is the precursor to an important aspect of machine learning, as he mentioned at the beginning. I guess he could make the connection more obvious from the start to hold interest for those of us who don't immediately see it. I suspect that you feel like I do, that pressing on the feeder bar labeled "Followed by" will bring the main point closer, after three times it is frustrating. My one suggestion would be to combine all three into one article and stop teasing us. I'm hooked, but they were short enough to put them all together.