This is spot on, I've wondered about the economics of scarcity for a while. How does it apply to selling accounts for a hot web service? Maybe give them away for free while you're obscure, grant invitation privileges to the early adopters and start charging when the mass of users rolls in. Bonus points for raising the price, the more well-known you become. Can you share your success with the early adopters? Maybe allow them to sell their contingent of free accounts somehow?