Being logged in on XMPP chat with same nick from several places
If you use different devices for your XMPP chat, it can be a chore to have different nicks just so that you do not get kicked out or blocked when you log in from device number 2.
Newer versions of ejabberd (13.10 tested) allows this by default, however the old version (2.1.2) shipped with Ubuntu 10.4 does not. Openfire did not allow it in the version I tested, and it seems that it is not possible.