From WoWWiki

Articles in this category have a large number of external links that could be converted to internal links (or a combination of internal/external links). The articles these pages link to may already exist in WoWWiki or they may need to be created. Converting links to internal links allows Wikians to control and monitor the content to provide the best information. It also encourages pages that don't exist to be created.

Many of the articles in this category will have the {{elinks-vio}} template in their wikicode.

Note however that there is little point in just duplicating the information in the WoW database sites for every little itty bit of equipment or for every little mob there is in the game. The power of Wikis is to collate useful information, actual human input, and format it in a way that is easily accessible to visitors. Splitting the contributors' efforts over tens of thousands of little pages makes little sense. Concentrating the efforts on actually useful pages, where people can provide meaningful input, makes a lot more sense. So, please, don't just Wikify something because it didn't exist in WoWWiki. Pick something where we can make a real difference!

See also: Help:Link#External vs. Internal Links