There's a Do-Not-Disturb mode already.

Leaving open, since indeed we don't have a whitelist-blacklist mechanism yet.

I opened a discussion thread on DEV ML about it.

There is some RFC for this mechanism:

"2.3.  Privacy and Policy

   The rich presence capabilities defined by the specifications in
   Section 2.2 introduces a strong need for privacy preferences.  Users
   must be able to approve or deny subscriptions to their presence, and
   indicate what information such watchers can see.  In SIMPLE, this is
   accomplished through policy documents, uploaded to the presence
   server using the provisioning mechanisms in Section 2.4.

   RFC 4745, Common Policy: A Document Format for Expressing Privacy
   Preferences (S):  [RFC4745] defines a general XML framework for
      expressing privacy preferences for both geolocation information
      and presence information.  It introduces the concepts of
      conditions, actions and transformations that are applied to
      privacy-sensitive data.  The common policy framework provides
      privacy-safety, a property by which network error or version
      incompatibilities can never cause more information to be revealed
      to a watcher than the user would otherwise desire.

   RFC 5025, Presence Authorization Rules (S):  [RFC5025] uses the
      framework of RFC 4745 to define a policy document format for
      describing presence privacy policies.  Besides basic yes/no
      approvals, this format allows a user to control what kind of
      information a watcher is allowed to see.

   RFC 3857, A Watcher Information Event Template Package for SIP (S):
      [RFC3857], also known as watcherinfo, provides a mechanism for a
      user agent to find out what subscriptions are in place for a
      particular event package.  Though it was defined to be used for
      any event package, it has particular applicability for presence.
      It is used to provide reactive authorization.  With reactive
      authorization, a user gets alerted if someone tries to subscribe
      to their presence, so that they may provide an authorization
      decision.  Watcherinfo is used to provide the alert that someone
      has subscribed to a user's presence.

   RFC 3858, An Extensible Markup Language (XML) Based Format for
   Watcher Information (S):  [RFC3858] is the companion to RFC 3857.  It
      specifies the XML format of watcherinfo that is carried in
      notifications for the event template package in RFC 3857."

From http://www.ietf.org/internet-drafts/draft-ietf-simple-simple-02.txt

*** This bug has been marked as a duplicate of 454342 ***