Disc sales is going to be an important variable because it will influence the studios behavior with regards to releasing titles. If I'm Columbia Tristar and I don't want to go through the expense of creating and distributing two different HD versions of a new movie, I'm going to think long and hard about which version of disc is out-selling the other by a 2:1 margin. Twice as many potential sales is a big deal to me. The same goes for justifying rescanning older films for release in HD. No reason to go through the expense unless there is profit to be made and as a movie distributor there is currently twice as much profit (all other things being equal, of course) to be made with BluRay So if brisker sales of BluRay titles cause the library total available BluRay library to grow much bigger than HD-DVD, that is going to drive hardware sales.