http://qwikxxeiw4kgmml6vjw2bsxtviuwjce735dunai2djhu6q7qbacq73id.onion/articles/xmpp/intro
The difference is that private rooms supports encryption
and you must be invited to enter it. Public rooms, on the other hand, only requires you to know the address to join, although
you can also be invited to a public room. Public rooms do not support encryption . Once you have created a room you should be able to invite your friends through the client, otherwise you could try giving them
the address.