Web Directories can be broadly categories into General directory, SEO Directory, paid directory, free directory, Directory of directories and the most recent addition to the directory family, Bid for Position directory, also know as bid for placement directory.
Bid for position directories first came into the market sometime last year, when a site called Dollar Linking started what seem to be a revolutionary was of meeting webmasters quest for their site to be placed above their competition in a categorised listing. Dollar Linking simply list your site based on how much you pay, a concept that is not unlike the algorithm used by Pay Per Click search engines; the more you pay for your keyword, the higher your site is listed.