>>27394929tl;dr version:
If your story has Anon and it takes place in equestria, it fits here. There's some unspoken nuances, such as anon being not an equestrian native, but that's the tl;dr.
Some anons might try shitting on you if you include something they don't like (hi antiTFfag), but this is 4chan, some shitting is to be expected. It also helps if your writing skills are half decent, meaning proper capitalization/punctuation and such things.
ps don't be an attention whore