Googles collection of web sites sharing sensitive directories. The files contained in here will vary from sensitive to über-secret!
These searches reveal servers with specific vulnerabilities. These are found in a different way than the searches found in the "Vulnerable Files" section.
These pages contain such things as firewall logs, honeypot logs, network information, IDS logs... All sorts of fun stuff!
These files contain usernames, but no passwords... Still, Google finding usernames on a web site.
Examples of queries that can reveal online shopping infomation like customer data, suppliers, orders, credit card numbers, credit card info, etc
These searches locate vulnerable servers. These searches are often generated from various security advisory posts, and in many cases are product or version-specific.