@darius i'm not sure what the point of such a *server* would be, but as a *client*, i imagine it would make some sense. i'm thinking generic activitypub server and then an activitypub client that just shows you your inbox. i mean, everything is a "direct message" on the spec level, right? just, you're dealing indirectly with resources. perhaps you could have a separate Message activity, but it is also conceivable to add certain objects to a certain collection. maybe even both of these ideas.