Internet directories can be considered another kind of search engines. Instead of using “crawlers,” Internet directories compile and rank large databases of webpages by using human power to manually find and sort relevant webpages. Such “directories” employ human editors to compile their databases. Most Internet directories are covered in this section.

Some time ago, directories were not as numerous as they are today, but their popularity was greater because the technologies powering their competitors’ crawler-based search engines were not as advanced as those of today, which allowed Internet directories to offer much more refined and relevant content. To be listed in a directory like Yahoo! Directory or DMOZ meant good and targeted traffic.

Today, almost every industry and branch of human knowledge seems to have its own directory in the Internet, so it's not strange to find a “directory of directories.” Such sites aim at categorizing existing catalogues, but in general, they do nothing but make the picture more complicated. Ah, yes. They also tell search engine optimizers to which else Internet directories they can submit their sites to get a backlink.

Still, a DMOZ or Yahoo! directory listing can do a lot for your SE rankings because every month, Google begins crawling the Web from the DMOZ pages and Yahoo! from its own directory. Links from established and recognized Internet directories are a powerful contribution to your overall link popularity and Web visibility. However, it's difficult to get there. Before your site gets listed, an editor must review it to decide whether it is appropriate for a certain category. That’s why it is not enough to write a keyword-rich text copy; you must create a website that is attractive, appealing, unique, and easy to read in order to make it into an Internet directory.