Whatsapp is currently the top messenger service which offers unlimited text messaging including photo, audio and video. You can also send contacts as vCard. If you want to share your location, this facility is also there. It also allows you to create a group for group chatting. You can create a broadcast list if you want to send messages to multiple contacts but in order to receive such messages they must have your number in their contact list. Now all these services are provided by whatsapp for free for the first year. From the second year its only $ .99 per year that is Rs 67 (approximately). For this type of service even ten times of the current price is justified. They also do not serve ads which could have generated lots of money. But last year whatsapp decided to make it free for Indian users. Now no more subscription charges is require for Indian users So, how whatsapp earns without taking subscription charges and even without displaying ads ?
How whatsapp earns ?
Downloading their app costs money. In the U.S. market in April, WhatsApp racked up $355,000 from Apple’s App Store. But that is only limited to iOS users. For Android, Symbian, etc downloading this app is free in some countries. Tie up with telecom companies is also a factor. Telecom companies who provides whatsapp data plan may have to pay money to whatsapp. 
Currently, information is a very valuable entity. Big companies can pay a lot to get the relevant information. Based on that they can build their service or product so that it is readily accepted and used by the end users. Though whatsapp promise not to sell data but according to speculation the revenue generation for whatsapp is primarily through information selling. All the conversations on whatsapp are backed up on whatsapp servers constantly. Our conversations reflect our interests, likes, dislikes and majorly depicts our preferences. This information is invaluable to big firms where relevant tailor made products can be offered after data sorting. Earlier companies used to spend millions on surveying to know the potential customer’s needs but now its just a click away if presented by whatsapp in a classified way. So this has the potential to generate huge revenue considering the gigantic userbase of whatsapp which is increasing exponentially along with time.