It's the modern epidemic that's worsening by the day: the omnipresence of the smartphone. On the loo (my favourite spot to tweet from), on the bus, in bed, in the middle of meetings, at dinner, during s--- yep, seriously, some people do it.
Perhaps one of the most striking features of WhatsApp is that, unlike other social networks, the users are not the product for sale. The company's founders are vehemently opposed to the idea of introducing any type of advertising onto the platform. You pay to use WhatsApp.