I was reluctant to bring this up because of all the drama of NIP-10 and NIP-27, but I think the current solution is still wrong. Quotes of a post should be indexable and able to be viewed.

This is related to #523

I would propose using a "q" tag. It's effectively the same as "e" except it's explicitly a quoted event on kind 1 notes, where "e" is just a reply.