Potter was really hardline with shipping, who was shipped with whom, especially amongst the main three characters. Even writers in the 'gay' ships had some pretty homophobic ideas about what was a 'real' relationship. Friendships broke up over who they thought would top or bottom. (Changing it up in your stories was seen as a bit weird.) Communities were really separate based on shipping lines. A friend of mine ran one of the fests that was open to multiships, I wrote for that a bunch of times. It was a great little fest, but I'd still get weird comments from people sometimes who didn't approve of the ship or dynamic I chose to write.