The WhatsApp Architecture Facebook Bought for $19B (2014)

There's an article at the front page about WhatsApp and how they manage to do a lot with a little. Unfortunately, it doesn't go into much technical detail. I figured this article is more appropriate for the HN audience.

This is also a good article with a slightly different focus: http://highscalability.com/blog/2014/3/31/how-whatsapp-grew-...