Whatsapp is an app not a technology - the protocols allowibg users to communicate through whatsapp are the real innovation there

Whatsapp was cross platform and free.

Skype was cross-platform and free too. Also, we are talking technology, their pricing strategy is a different problem.

No, you have to take in the context and timeframe.

Skype was not a messaging platform that regular users used on their Phone.

iPhone and Android each were their own bubble and required paid expensive SMS messages to talk to each other.

Whatsapp was at least very populair in The Netherlands for this reason alone.

Pricing is important because that proves why it was useful to people. Also: ease of use, based on how Whatsapp works.

We are not talking just technologies but technologies in a context.