India finally seems to be responding to viral marketing. After Orkut that seems to have taken off on back of viral marketing, last month showed a brilliant run (globally, but in India as well – its Alexa 33 for India already) on back of suck-email-addresses-and-send-invites functionality. Some of the local social networking sites also seem to be headed for critical mass.

The manner in which Orkut took off seems to be very different from though. Orkut seemed more organic unlike the mass messaging style of Earlier, I believe hi5 had followed the same path. While this helps create quick base of users, wanted to get people’s views on what really makes them stick? What is the set of “local features” that Indian social networking sites can create to provide a superior offering to Indian consumers? One of the clear answers seem to be mobile interface to site functionality. The other one perhaps is local content such as bollywood. However, community is the central product of a social network, and that gets created automatically on a site as you get more people on.

Would love to hear from folks here on what they think is the killer app on social networking, which is their favorite network and why?