Just like international callback services from ye olde times (1990s) http://en.wikipedia.org/wiki/Callback_(telecommunications)
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In India, the “missed call” as a means of communication and interaction has developed into a cultural and business norm.
Also:
Missed calls are being incorporated into mobile apps and services as a standard type of messaging like a text or an answered call itself. For example, an Indian cloud telephony service provider startup called KooKoo has been working with a Bangalore-based company to create an information market based around missed calls. If you want to know the latest weather, the latest Groupon-style deal, or the real-time bus schedule, you can send a missed call to the designated number and get an automated or manual voice call back with the answers you need.
(Via GigaOm)
(Source: dbreunig)
