Board Thread:Support Requests - Getting Technical/@comment-9179092-20130511081051/@comment-24155515-20150927224954

When you include a template name within double brackets (i.e. parameter 1), it tells the wiki "hey, you should take the code that's on that template page (i.e. Template:Navbox) and pretend it's in that spot!" That's called a transclusion.

If you transclude the template in the template's page (i.e. put Navbox in Template:Navbox), then the wiki gets told "hey, transclude that page here!" but also has a ('louder') voice telling it "hey, that template link has the same name as the page we're on! We can't put that template in this page because it is this page and we'll just be putting the page in itself for forever!" So it puts an error message instead. (It doesn't have to wipe out other template text, I don't think, though a lot of the loops I've seen in the past have been a user replacing the whole page with the loop trigger. The ones I've seen have been users without a good grasp on wiki/template coding.) Any template with a loop detected on the template page will display the error on any page it's transcluded to, I believe.

Hmm... *suddenly wonders if Wikia allows transclusions that could demonstrate a loop error here... but probably not XD* (EDIT: It works, but not the way I was going for. XD)