Very interesting, it didn't occur to me that hardware products would show up on Steam's top-sellers list.

At this rate, the Steam Machine will probably turn out to be a modest success. Remember, it's a PC, not a console. Unlike a console, it doesn't need to use hardware sales to convince game developers to ship games for the platform; the PC platform does not depend on the Steam Machine selling like hotcakes. Also unlike a console, Valve isn't selling these at a loss; Sony can sell you hardware at a loss because they claw that money back via online subscriptions and platform licensing fees. Valve will likely be happy enough if they can sell 100,000 by the end of the year, and based on these estimates they may already be about halfway there.