anchor.diff:  %% for a particular key.
   %% @TODO Consider other options that would give more
   %% assurance that a particular email address is available.
  --spec email_available(string(), pid()) -> true | {false, term()}.
  +-spec email_available(binary(), pid()) -> true | {false, term()}.
   email_available(Email, RiakPid) ->
       case riakc_pb_socket:get_index(RiakPid, ?USER_BUCKET, ?EMAIL_INDEX, Email) of
           {ok, []} ->
  
positive.code:     %% @TODO Check for missing fields
      UserName = binary_to_list(proplists:get_value(<<"name">>, UserFields, <<>>)),
      DisplayName = binary_to_list(proplists:get_value(<<"display_name">>, UserFields, <<>>)),
      Email= binary_to_list(proplists:get_value(<<"email">>, UserFields, <<>>)),
      KeyId = binary_to_list(proplists:get_value(<<"key_id">>, UserFields, <<>>)),
      KeySecret = binary_to_list(proplists:get_value(<<"key_secret">>, UserFields, <<>>)),
      CanonicalId = binary_to_list(proplists:get_value(<<"canonical_id">>, UserFields, <<>>)),
  
negative.code:                 true ->
                      User = ?MOSS_USER{name=UserName,
                                        display_name=DisplayName,
                                        email=binary_to_list(Email),
                                        key_id=KeyId,
                                        key_secret=KeySecret,
                                        canonical_id=CanonicalId},
  