https://www.mindtheproduct.com/whatsapp-power-product-focus/
WhatsApp has managed to achieve their staggering growth in part because they’ve eschewed the traditional free or freemium model in mobile apps. Their app is free to download, and costs just 99 cents per user after the first year. This has meant that they’ve been able to avoid monetising their app through advertising – something that would have detracted from the user experience of the product.
“Utilities get out of the way. Can you imagine if you flipped a light switch and had to watch an ad before you got electricity? Can you imagine if you turned on a faucet and had to watch an ad before the water came out?”
Jan Koum, WhatsApp co-founder and CEO