Red link

A red link is a wiki link which does not point to an actual, existing wiki page. It shows up as a red-coloured link to indicate this.

While red links may seem unsightly--and should not be used on official pages--they are actually very valuable on normal wiki pages, because they usually indicate some concept that a contributor thought was important enough to wikify, but did not have the time or expertise at the moment to properly make an actual wiki page about. As such, the yet-to-exist pages that are pointed to by red links are called wanted pages. A list of wanted pages can be seen at Special:WantedPages, organized by most wanted first.

Leaving red links in the wiki is like leaving footprints in the snow.