Abstract: The present invention relates to an appointment invitation method comprising: sending via a messaging module an invitation message comprising a time information, as well as an optional attendee information and/or an optional location information, for an appointment from an inviter to at least one invitees; receiving via the messaging module one or more responses from the at least one invitees indicating an acknowledgement, acceptance, desirable amendment, or rejection to the appointment; and determining the appointment or negotiating/rescheduling the appointment based at least partly on the one or more responses received from the at least one invitees until the appointment is determined. The present invention enables a better utilization of time by transferring real time and more interactive communications for negotiating and determining various kinds of appointments between desired attendees while preventing disclosure of undesired personal particulars thereof.