[shedletsky]

Depending on how cynical one is, you might view the real estate multiple listing service (MLS) as "community owned", at least from a game theoretic standpoint.

It is not a monolithic organization. There are actually 850 regional MLSs in the US. In some sense this is a P2P walled-garden marketplace. However, there is downward pressure from the national realtors association to standardize on things like listing formatting, so it is not entirely self-organizing.

I think owning the marketplace is valuable. Similar to various open source initiatives, once the free marketplace gets to a certain size, someone like Red Hat will come in, fork it, and set themselves up as gatekeepers. The resting dynamic of the system is a feudal kingdom.

My 2c