A Wiki Badge to highlight a broken external link. Because the page may be unavailable only temporarily, the link should be checked a number of times before deleting it or looking for a replacement.
If the target page really does seem to have vanished, try using the Google Cache or the Wayback Machine to find the page. You may even be able to use Google Search to find a replacement link and repair the affected Wiki Page. Sometimes it's not possible. See Rescuing Broken Links for an idea to help make it more possible for future editors.
For preference, use Broken Link only when you see a link that's broken but can't find a replacement.
You might like to annotate the tag with actions you have tried. Sooner or later, a visitor will use this information and take the appropriate action:
remove Broken Link
replace the link
remove the link
Click on the title of this page to see a list of Broken Links, and if you can fix some, please do.
If you find one of those old style external links ([1] [2], etc.), follow the instructions on Fixing Links instead of adding Broken Link to the page.
Tip: Sometimes, only the server a page is on changes. You can search for it by URL
in Alta Vista:
+url:PageName.html
in Google Search:
inurl:PageName.html
Tip: Some broken links are marked with the text 'dead link' or 'broken link', making them kind of hard to search for.
One can use the C2 Search Helper to search for 'dead' AND 'link' (or 'broken' AND 'link').
Also, Google searches for www.google.com 
and www.google.com are effective.
The Internet Archive can be helpful in that it may help you see the missing content. This may give you useful terms to search on, in order to find other copies of published content.
See original on c2.com