[Peter_Spaeth]

The set registry as an "essential facility"? That would be the applicable doctrine. Like real estate multi-lists, or football stadiums? I'll have to think about that one, it's an interesting point.

For background, in one sentence, there is an exception to the "refusal to deal" line of authority that says when a monopolist controls a "facility" and sharing it is "essential" to the existence of any competition, the monopolist may have to grant access. The doctrine originated, I recall, in a case involving a firm that controlled the only railroad bridge, I forget where now. It's also been applied, again from memory, to advertising in a town's dominant newspaper, real estate multi-listing services, and a football stadium. That said, it's usually construed pretty narrowly.