Then when the same iPhone app seamlessly started sending iMessages (blue bubbles) to other iPhones rather than SMS (green bubbles), people just kept using that.
When Whatsapp launched, SMS still wasn't free, the exception being some carriers that offered "free" SMS to numbers of the same carrier if the sender was on a premium coverage plan. In sum, majority of the population was still paying $0,10-$0,20 despite already having data plans. So it was an easy win for WhatsApp.
I see this listed as the reason often but I had unlimited SMS then too. In fact I remember visiting the US in 2009 and I was charged to send AND receive an SMS which was a shock.
I think the actual reason is that communication across borders in Europe is very common and those SMS's were not included in the unlimited plans as they were messages abroad. So they were subject to fees (usually high ones). I think this is the reason it was common - especially given how common it is for students to study 'abroad' in other European countries. There were a few competing apps for this at the time (Vibr I think was another but was more call focussed) but WhatsApp won in the end.
> I think the actual reason is that communication across borders in Europe is very common and those SMS's were not included in the unlimited plans as they were messages abroad. So they were subject to fees (usually high ones).
So, you completely agree with what you seem to be taking issue with.
Interesting! I haven't heard mention of Viber since around 2011. When I said WhatsApp 'won' I meant that wherever I have been in Europe WhatsApp seems to be in use by people and by businesses. It's almost accepted you'll have an account and used as an alternative to email/phone numbers. I understand global MAU may show a different reality and certain locales may still be dominated by other platforms.