Moderators can move comments to a chat room associated with the post, and now we don't even have to wait for 20 comments to be posted in a short period of time -- we can do this at any time via the mod menu. This is great; it gives people a place to have that tangential discussion that might be valuable but isn't about the post any more and doesn't belong on the main site.
Here's the problem: we move comments to chat, which leaves an auto-generated comment saying "comments have been moved to chat (link)". And then some people continue the discussion in chat but other people keep commenting. At that point our choices are:
- delete the comments (failure to follow directions), but users think this is mean and it's also tedious to do (have to either delete them individually or purge and then dig through the big pile to undelete the "moved to chat" comment buried in the middle)
- leave it alone, but then we're being inconsistent (why did those have to move but not these?)
- hand-copy them into the chat room, which is a lot to ask of moderators (translation: no)
The "move comments to chat" feature is single-use; once it's been used on a post it's grayed out on the menu, presumably because bad things would happen if it tried to create the same chat room a second time.
Would it be possible for that option to remain (optionally renamed "add comments to chat" if you think that's valuable), with later invocations adding new comments to the existing room? It could find the comment with the link to the room (which might or might not be the earliest comment on the post), and then send everything after that comment to the existing room. (It wouldn't need to generate a new auto-comment, but it would need to make sure those users can chat in that room, same as the current behavior.)
One might ask why we shouldn't instead just shut down comments after a move to chat -- once there's a chat room, force everything there and take away the "add comment" link. Attractive as that idea is to me, it also prevents the (few) comments that are actually what comments are for -- requests for clarification. If we can come up with a practical way to add some friction for post-migration comments that'd be cool, but we're always going to end up with some comments that should be in the chat room but aren't. I'd like to have a way to send them there.