If a card (or "page" in most other wiki software) exists in this wiki, then making a link to it goes to that card.
With NearLinks, you can create a NearMap that will make a link go to other wikis that possess the same card name, if the card doesn't exist in this wiki.
The community of the wiki presumably decides what belongs on the NearMap
http://www.communitywiki.org/NearLink
http://www.communitywiki.org/NearMap
http://www.communitywiki.org/InterMap
This concept originated with http://oddmuse.org wiki engine, building off of InterWiki links concept from original WikiWikiWeb and MeatballWiki.
http://www.oddmuse.org/cgi-bin/oddmuse/Near_Links
+discussed in support tickets
+relevant user stories