There's a certain confusion, or duality, in the way Wikipedia links work. If you access a director's page for example, and a sentence states he has made "20 movies", clicking on "movies" can either take you to his separate filmography page or to the general article "Movie". I believe only the first option should be manually defined.

The Free Dictionary uses something like that - try double clicking words within the definition: http://www.thefreedictionary.com/link