@dansup @activitypub you can use Duration for passing around the amount of time that the AP object will be around. After that propagate a Delete for it maybe(?).
However you have to rely on services/apps honoring them, which might not be what users expect.
@mariusor @activitypub Well, for one we use a custom activity type, and duration is used to denote the length of each story. We will send Deletes and have an expires field too