The editors, over 58,000 of them, are unpaid volunteers, nameless internet users who devote some of their time to indexing websites under certain categories. A new volunteer is usually given a very small, very specific category to edit. That editor is then responsible for finding and adding new website that relevant to the category. As the editor gains experience he can move up the ladder and take on larger and more complex categories. All categories are subject to review and change from higher-ranking editors. For an organization made up largely of unpaid volunteers it is incredibly well done and. I often use the site when researching a specific topic. Think of it like About.com without the annoying excess of advertising.
Indeed, the categories are so useful that the ODP is used as the core directory for the web's largest search engines, namely Netscape Search, AOL Search, Google, Lycos, HotBot, and DirectHit. Because of this, submitting the URL for your website to the ODP is the quickest way to getting your page listed.
Despite listing nearly 4 million websites in 460,000 categories, the ODP still needs help. As a former editor I can say that it is actually pretty easy and can be fun. Choose a category which is interesting to you and you'll soon find yourself addicted to finding new websites to be included. Head on over and sign up. Its a lot of fun.