So you know how you putt in all the tags for your story, and there's the relationship field? Well, that can be used to describe any kind of relationship in the fic, not just romantic pairings (which is what I had always assumed).
[Character Name] & [Character Name] = Rivals, enemies, friends, family, etc.
[Character Name]/[Character Name] = romance
I've gone in and fixed this on my stories. Personally, I just tag the relationships that are actually important to the story, because there's an issue of people tagging every single ship, including background ones. If you want to read something featuring a particular couple and try searching for it, in some cases you'll get back a bunch of results where said couple just gets a mention or the like. It is pretty annoying.