Instant messaging was transformative. It was adopted not because of a bright, shiny project roadshow, but because users chose to embrace it.
Because instant messaging works better when your connections are on the platform too.
Brian Acton and Jan Koum realised this when they created WhatsApp. Their early version showed statuses next to individual names of the people. This is a marginal benefit, not much to get excited about.
But once users were able to message each other, share photos, and group chat everything shifted. Now, you were in one of two camps: on WhatsApp or off WhatsApp. And if you were excluded, off WhatsApp, that was problematic. And the more people who joined WhatsApp, the more people talked about WhatsApp. This snowball effect made exclusion even more problematic.