The manner in which comments are moved to chat on "noisy" websites is incredibly disruptive. It goes something like this:
- Several comments are moved to chat by a moderator and linked to the chat room.
- More comments are written under the post.
- Moderator returns and deletes all of the new comments, leaving a new comment "Comments cannot be moved to chat twice. Any further comments will be deleted."
The workflow for moving comments to chat is very haphazard. You never know when the "would you like to move this conversation to chat" link will appear, and when it does, it doesn't actually move the comments, nor does it "move" all of them. This is also true of moderator chat conversions.
The policy of deleting further comments because they can't be moved into the chatroom is just terrible in so many ways.
So here is what I suggest:
When the number of comments under a given post reaches a certain, site-specific threshold, move all of the comments to a new chatroom.
Leave a link to the new chatroom under the post.
When the "Add a comment" link is clicked, redirect to the chat room.
Turn on OP notifications in the chatroom, so that folks asking for question clarification will get attention from the OP. Alternatively, allow the OP to be addressed directly in the chat room, even if he hasn't commented previously.