The service allows you finding out who has called you, when the telephone line was busy, switched off or was outside the zone of coverage. By doing so, it ensures that an important call will not be missed.
A mobile dialer or a soft dialer is an application allowing the users of the cell phones to make VoIP calls via a mobile device with Internet connection. Such a thing of making call this way is called mVoIP or Mobile VoIP. This mobile dialer can be used by various companies trying to reduce the operational expenditures or by individual who just want to save extra money on the phone bills.