Travel agents are another group that has survived on exclusive access to information.

ECONOMIST: Electronic commerce

These agents waste time competing with each other for the exclusive right to sell each home, sapping productivity.

ECONOMIST: American property: The great realtor rip-off | The

There is no "typical" castle buyer, but Russians have been the most recent group to enter the exclusive German market and can sink huge amounts of money into buying and renovating castles, agents say.

WSJ: Castle, Sweet Castle