Walking into an empty space posts a card in the conversation it belongs to. It is how everybody reading finds out that something is happening in there, and it is a message like any other: it stays in the scrollback, and somebody scrolling past tomorrow still sees it.
While it lasts
The card counts who is inside and names a few of them, and it keeps up on its own as people come and go. Walking into a space somebody is already in posts nothing: one gathering, one card.
Once everybody has gone
The same card becomes the record of what happened: how long the gathering ran, and how many different people came. The address itself does not expire — a space is a place — so the entry beside the tabs still posts a card for it, and the next person in starts a new gathering.
Who posts one
Only a registered nickname. A shared address carries somebody accountable for it, which is the same rule every other link in this chat follows. A guest walks into the space exactly as usual; there is simply no card, because there is nobody to put on it.
See also: Virtual Spaces · A Space in Its Own Tab · Inviting Someone to a Space
