What happens to comments which are moved to chat as times passes by? Are they conserved, or do they disappear after a time?

This is triggered by the question Ground state of local parent Hamiltonians and invariance under local unitaries (which got bumped by the Community bot) -- I remember there being a number of comments about clarifying the question, and I don't believe that these discussions have made it into the question. Unfortunately, the link to chat leads to no-where -- is there a way to recover these comments, or are they forever lost?


2 Answers 2


The answer to your question is in the retention item of the chat FAQ.

That said, moderators can still see the contents of the deleted room and I have undeleted the one under discussion. The system will doubtless reap it again in a couple of weeks.

  • $\begingroup$ Thanks. I'll try to have a look and incorporate them into the question. EDIT: Do I see correctly that one extra comment would preserve the chat room? (There are currently 14 comments.) $\endgroup$ Nov 7, 2016 at 16:58
  • $\begingroup$ Seems so. You could post one message so that it gets frozen instead of being deleted. $\endgroup$
    – David Z
    Nov 7, 2016 at 19:05
  • $\begingroup$ It's already gone again ... that was fast. $\endgroup$ Nov 10, 2016 at 8:52

As dmckee points out, the answer is in the Message Retention section of the chat FAQ:

Will these rooms exist forever?

Rooms will exist indefinitely, so long as there is at least one person actively talking in the room. A room is considered worth retaining if it has more than 15 messages by at least 2 users.

deleted and frozen rooms http://cdn-chat.sstatic.net/chat/Img/faq-deleted-frozen-rooms.png?v=e77e86064bd6

Rooms not worth retaining which are inactive for 7 days will be deleted. Rooms worth retaining which are inactive for 14 days will be frozen. Frozen rooms do not allow any new messages to be sent, and are not shown in the default room list to prevent cluttering the rooms interface.

The thread you refer to has exactly 15 messages, so apparently it was one message short of qualifying. (It needs a full 16 messages (i.e. (strictly) more than 15) to survive. At undeletion it had 15 - note that this and this are separate messages.)


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