Several types of communication techniques, including telephone calls, video conference, Voice over IP (VoIP), and instant messaging are valued because they allow persons to communicate in real-time, without delays associated with communication techniques such as letter writing, email, and other types of messaging. Because people often turn to real-time communication techniques with the hope that they can establish immediate contact with persons they are trying to reach, it is often frustrating when a communication attempt of this type fails (e.g., because a person to is unavailable to respond to an incoming call or message). In such a case, the person attempting to establish the communication has few other options but to try again later, leave a voice message, leave an email, try contacting the person on another device, etc.