Comments are support tickets with an audience

A comment is a support request that everybody can see. It needs the same queue, the same response time and the same care as a DM, plus one judgement a DM never needs: whether to answer where it was asked.

The three that go private

1. Anything needing an order number, address or phone. Asking for it in public invites everybody to see the answer, including people impersonating you.
2. A complaint with details you have not verified. Acknowledge publicly, resolve privately, come back publicly if it is resolved well.
3. Anything about somebody else. A commenter naming a staff member is a conversation to have out of view.

A private reply to a public comment is the tool for all three - it opens a DM thread tied to that comment, so the customer does not have to find you, and the public thread can carry one line saying you have messaged them.

What to answer in public

Anything a hundred other people are also wondering. Prices, hours, stock, whether you deliver there, what the warranty is. Every public answer is work you do not do again, and it is the closest thing social has to documentation.

Running comments as a queue

• One place with the DMs. Split across the native apps, comments are checked when somebody remembers.
• Unanswered is the sort. Same rule as the inbox: read is not answered.
• A stated moderation rule, published. "We remove abuse and spam" makes removal defensible and rare.
• Watch the older posts. Comments arrive on content from months ago, and nothing surfaces them except tooling that looks.

Hiding, and when it is honest

Hiding a comment leaves it visible to its author and their friends while removing it from everybody else. It is the right tool for spam and for abuse. It is a bad tool for criticism, because the author can see it is still there and can see that nobody responds - which reads worse than a reply would have.