User A: Requests presence subscription from User B
User B: Accepts subscription.
User A: Can now see User B’'s online presence.
User B though cannot see User A’'s presence because they havent requested it.
Now the default behaviour of most clients is if you accept a presence subscription to send a request back. The client who originally sent the request will automatically accept this as they have already requested subscription from the sending client.
The subscription type will then be “Both”.
Its quite a confusing topic tbh. Have a read of the RFC to clear up anything that still makes your head spin.