I disagree, for three reasons:

1) I'm not trying to ponify LessWrong. I post pony things here when they merit their own Discussion post on LessWrong. They are here as fully-qualified LessWrong discussion topics, not as pony ramblings. Otherwise, I'd rather see them in the fimfiction LessWrong group.

2) Creating a monthly pony thread would obligate people to put everything pony-related in that thread, even if it merited its own post. It would demote and degrade everything pony-related. It would ensure that nothing with the word "pony" ever reached Main.

3) It's rarely a good idea to ghettoize yourself.

HPMOR is a single story, so it makes sense for it to have its own post.

Let's at least wait and see whether the pony content increases.