Seriously-thats a dumb word to describe people talking about relationships in stories. Shipper? Lame.
Anyway... I brought up a plot point in an episode of Avatar the Last Air Bender and speculated if that would be brought up in the final episodes of the final season. This deals with who Katara might marry. Now... I don't usually talk about relationships in stories unless they are an important aspect to them. Avatar is one of those series because a)Aang likes Katara b)Sokka has had a relationship with two girls, one of which becomes the moon spirit c)Zuko and Mai.
In some series, relationships don't mean much but in others-they can make a good series better. And one of the things I do like about Avatar is that romance and love, as I see them, are important parts of the series. Aangs relationship with Katara would mean less if he didn't have feelings for her. I believe that to be more than an opinion. Zukos relationship with Mai represents his softening as an individual. Sokka's... well... not much but if he didn't have the brief moments with Yue in the final episodes of the first season would her sacrifice mean as much?
Now... back to my plot point. I actually watched a bunch of vids by someone on youtube whose sure that Katara and Zuko are going to end up together. They may have been looking too hard at certain episodes but they made some interesting points. Like how they represent ying and yang(for those unfamiliar with Avatar Zuko bends fire and Katara bends water) in their battle in the end of season one. In season two's final epsiodes talks about how Katara and Zuko did share a certain connection(before Zuko decides to once again side with his family). Also pointed out the way they spoke, the positioning of the characters and more as symbolic.
It does look that as season 3 comes to a close the two have regained that connection. If they don't get together, fine. Aang gets the girl and thats what he's wanted since he saw her. If Zuko and Katara do get together than its something more. It represents a union of sorts. The evil fire nations Prince and the daughter of a water tribe that suffered fromt he war.
Still... relationships and romance can mean a lot to a series/story. Writing it off as if its nothing due to the fact that ist not the focal point is rather naive.
Edit: Some novel with spoilers came out. I won't say anything other than the fact that the result is still, as I believe, an important ending to the subplot.
Anyway, season 3 AMV! I don't like the song but its a good vid.