I overlayed a graph of the Bitcoin-USD exchange rate (red/green/black), with a graph of search volume for the phrase “bitcoin” (blue), between January and September 2011:

A striking correlation, no?

In fact, its what you’d expect, surprisingly so in fact. Since the supply of new Bitcoins is regulated such that it is essentially constant, you’d expect the value of a Bitcoin to grown and shrink in proportion to the rate at which people are seeking to acquire Bitcoins.