From Wikidweb

To prevent spam, this wiki uses a whitelist for external links instead of a blacklist.

"Wait - this is a directory! How can you restrict external links?"

Yes, directory links are handled in a special way - each listing in the directory is the title of a new wiki entry - this is allowed to link externally. Additionally, subpages and subdomains of a listing may be referenced.

For example, if your listing is for You could also link to