Typical destinations of dead links are HTTP 404 or 403 errors or to a generic search engine-type page proclaiming, "This domain is up for sale!"
If you see a dead external link on this wiki, correct it or remove it. If you see a dead internal link, then, in the immortal words of the instructions that appear when you click on it, "Click the Edit button to start this new page."
If you find that you can't create this page because it has been locked, that's because it's either a member of the Permanent Red Link Club, or it was made and cut previously. Check the Permanent Red Link Club for it, and if it's not there, go to this forum thread and request an unlock.
This is one reason why Weblinks Are Not Examples.