Pick Directory is a web directory that allows users to bid on links to their website, with a starting bid of $1 guaranteeing a spot. Increasing one's bid can result in a higher position in the directory and placement in the Top 10 Link Leaders on the homepage. Buying links through this directory provides benefits like higher search engine rankings, more visitors to the website, and an increased Google PageRank, as link popularity is an important ranking factor for search engines.