[shadowgovt]

Store, purchase tracker, platform identification system, and analytics engine to push data on game performance and hardware configuration back to the Steam service itself as a mass aggregator so they can keep their finger on the "pulse" of real PC deployments and thereby come quite close to solving the problem that was once the bane of the entire industry ("Game doesn't work on my PC because drivers").

I think people tend to overlook how valuable Steam has been as a clearinghouse to aggregate that last piece of data.