I'm with Corndog on this one. Craigslist creates an even wider market, it doesn't ruin it. As a seller you can reach many more people through a CL ad as opposed to a local classified ad in the newspaper, and likewise buyers have many more bikes to choose from. It creates a more efficient market also. More buyers and more sellers equates to more transactions, equates to more transparency and a more efficient marketplace.
EastSideSM: '06 950SM Black