There appears to be some way of double posting to formats but it is unknown to me as of right not but I can assume that is is available through a coop covenant or exploitation. The only additional information I can really add is that the frequency of a message's appearance globally is dependent on it's current amount of ratings. It does not appear that these ratings need to be positive to affect frequency of appearance.

... until today when I fought against Lady Maria. She had 25% health left, I had less than 20% and was out of vials. That rating was all I needed to make it through alive

Does a note decay after time? Mine deleted after a couple days, without my consent.

I put down a note behind Patches that said, "despicable liar, let us cleanse these tarnished streets.", and someone rated it FOUL.
Who in the name of Kos likes PATCHES?!

I prefer the DS3 system where you get healed for downvotes. Let's you choose your alignment and benefit from it either way. Still in both games this is an underrated mechanic, messages that provoke a response (good or bad in DS3) can win you boss fights single handedly. For bloodborne just place good info near lamps and you'll receive a steady source of healing for basically free.

when I put an emote inside them it's always male despite my character being female, which really sucks because my armor changes looks depending on which you pick >:(