yo Mez , those heart reactions? they're kinda pseudo-private. if you like someone's note, only the note author sees who you are (via NIP-18 wrapped in NIP-04 DM), but if you *also* happen to rebroadcast it, then the whole relay sees the original note AND the heart, linking your pubkey to the like.

easy fix: just tick "private like" in most clients and it stays between you and the poster.