While I strongly support any business model that tries to escape from the typical ads monetisation strategy, we can see (two years after this post was published) that not relying on ads has not been the best long-term strategy for WhatsApp for two reasons: 1. They didn't manage to stay independent and had to sell to Facebook. I always thought that they had a very good chance to expand their product and built a platform that could truly challenge Facebook, Twitter, etc. 2. Now that they have been acquired by Facebook, we know that it is only a matter of time before an ad product is introduced into the service.