> I was just using this same number with SMS on dumb phones... why would I switch? We did use SMS extensively in the early 2000s. But many people also used thi

> I was just using this same number with SMS on dumb phones... why would I switch? We did use SMS extensively in the early 2000s. But many people also used things like Google Talk (and MSN Messenger on the PC) early on as it allowed you to send more than just text. MMS never really took off because not all phones supported it the same way and a lot of carriers charged for it (it also felt clunky). Once you get used to one app, it's easy to move to another one. WhatsApp quickly took off as it was very easy to set up (install, enter phone number, you're done), worked on literally any phone OS and was simple to use. It's a bit like wondering why everyone is using Slack when there's E-mail. iMessage was a non-starter because the iphone was just not that popular here (and still isn't what the majority use in most countries), so using an app that only works with a phone that less than half of your friends use made no sense.