The Open Directory, also known as DMOZ, is a large, categorized directory of websites and pages, which is staffed by volunteers. Every website and page that is added to the directory has to be manually reviewed before it is included. Being listed in the directory is free.

Not many people actually use the Open Directory for searches in the same way that Yahoo! is used, so the directory itself is of little value in generating traffic. However, its data can be freely downloaded, and any website, however small, can use it. One not so small website that downloads and uses the Open Directory’s data is Google. In fact, Google’s directory is the downloaded Open Directory.