A recent study found that Craigslist cost U.S. newspapers more than $5 billion in revenue over a seven year period. GigaOm’s Mathew Ingram rightly explains that there were a whole lot of other factors that played a role in the decline of newspapers (for example, a little thing we like to call the Internet). But it’s certainly worth noting the demise of the classifieds section. The best thing Jeff Bezos can do for The Washington Post is to figure out how to bring some version of the classifieds back. In the Internet business, getting close to the transaction is the name of the game.