WhatsApp announced today via a company blog post that it would be dropping its $0.99 annual subscription fee. In their blog post, they admit that this approach has failed to work well as a lot of their subscribers do not have access to debit or credit cards, which is something WhatsApp needs to take the blame. Having failed to consider alternatives such as carrier billing which is a common practice with carriers using it to sell everything from ringtones to callertunes.
The Facebook owned service would be looking towards offering businesses and services communicate with subscribers instead of ads. Such services could be a way for you to communicate with your bank about a transaction or an airline as regards a delayed flight.
I think this move by WhatsApp is great, since it has never really compelled users to pay for its services and with the plethora of messaging services out there, there's really no reason to pay anyway.
Source: WhatsApp Blog