Well I feel that 70% of customers would be unhappy with their service provider and would like to change. BSNL seems to be the best in connectivity, but their service is poor. Airtel has a good reputation, but their billing is an issue. Vodafone seems to be decent in service and billing. Reliance...
It is mainly because of games. But the concept of social networking at the click of a mouse and user-friendly features are what attracts people to facebook.