Seth Godin found, and bought, a copy of the the first big full page advertisement he ever did in a magazine. Where'd he find it?
Someone is selling it on eBay. (Not any more, I bought it for $5). This guy buys old magazines and sells them online, one page at a time!
Is there a buyer for every page, for every ad, for every headline? Nope. Doesn't matter. Because for this ad, for this page, here I was.
The long tail really does open up an amazing array of products and services: If you could buy thousands of old magazines for pennies each, separate, scan and post the pages for sale, manage the payments and shipment automatically, how many pages would you have to sell for $5 to make a few hundred million dollars?