who is going to see the text, and when will they see it? is a person expected to keep revisiting every reply in a topic to see if any new boosts have turned up?
what’s the chance of toxic content appearing in boosts? who will see, who will police?
what’s the chance of a side-conversation happening within boosts?
I very much hope this is optional: it doesn’t seem attractive to me for my forums.
(And if it doesn’t chance the order or promotion of a reply, I think boost is a poor name. Quip seems better, but that’s possibly not a widely enough understood word.)