I think that his observation on the goals of users and the effects of infinite scroll where particularly astute. I can see how on sites like reddit or imgur, where aimless browsing without specific intent could be a good thing, but I also see how a sudden lack of information (say, the number of items returned by a search query) can hamper the users ability to use the site how they intend (to search for products that they like). However, I do wonder if it's possible to mesh the two goals: increased utility for the user in searching for a product, while also integrating an infinite-scroll like feature. For instance, continue to show the list of products, but allow the user to load more products by scrolling to the end of the page. Even within my suggestion, there are better and worse ways to implement infinite-scroll functionality, each with varying levels of effectiveness.