From The New York Times : If You Liked This, Sure to Love That – Winning the Netflix Prize

…shopping over the Web is not a social experience; there are no clever clerks to ask for advice. What’s more, because they have no real space constraints, online stores like Amazon or iTunes can stock millions of titles, making a stack search essentially impossible. This creates the classic problem of choice: how do you decide among an effectively infinite number of options?

…even though Net­flix has a good deal of demographic information about its users, the company does not currently use it much to generate movie recommendations; merely knowing who people are, paradoxically, isn’t very predictive of their movie tastes.

The key feature here is the date: 2008. The Netflix contest folded in 2009.
(via Kottke, again)