To help people get up to speed faster and prevent backtracking, commonly asked questions by those getting involved are listed here with an answer.
=== Why not Is this going to use XMPP? ===
XMPP provides some components It quite possibly will! However, its useful to remember that are similar to what Mozilla Presence needs, however there's several parts that don't mesh well requiring either a rewrite or a fairly large layer on topis in very early stages at this moment. This Worrying about the exact implementation is generally because XMPP uses a Federated globally unique ID system with domain prefixing. Due to privacy concerns, detail that we don't want Presence re not addressing yet as we build some prototypes to maintain a list of a users 'contacts', nor should any AppService see the same underlying user with test concepts out and their FxA ID. That is why Mozilla Presence assigns a different UID for every AppService that a user allows to see their presence. It is entirely possible though that we might implement prove the channel between Presence and AppServices using XMPP which would make it easier for alternate presence providers (ie, if Google decided Chrome should have Presence in a similar manner)overall concept.
=== Shouldn't Mozilla have a way for me to see my contacts online? ===
