Let's say we are all trading clan tags. There are 0 tags being traded for the Paper Tigers. Thus, supply is 0. But everyone would want to be that one person in control of a clan -- therefore, demand is high.
We're not currently trading clan tags. But it would be interesting if we did! I'm not mathematically inclined enough to start this idea, but maybe someone else could take the reins, and create a 'stock market' for trading clan tags? The clans with more players would be valued less per tag due to high supply, but tags from clans with fewer members (and perhaps high competitive skill) would be worth more due to rarity.