DM clearing functionality
it would be nice if there was some means of deleting DMs, either for the admin (perhaps yearly pruning it) or as the user
use case: it's been a year since I told friend X that Y. We both know it. We both have saved it if we wanted to. that Y is a risk to keep around because sooner or later someone will pwn the server.
and yeah, sure the other server could still have it but the point is on that server.