"None the less, I'm not sure there's ever been a platform in history that knew so much about people, monitored publisher effectiveness so closely and made subscription so easy for such an incredible number of people."

So he doesn't mean powerful in the sense that it's the best recommendation algorithm, just that it has a lot of data. If having data in your domain is of course a necessary condition in developing a good recommendation engine. But if it were sufficient Netflix wouldn't have to shell out $1M to outsource the task.