Brian and I spent a combined 20 years at Yahoo!, working hard to keep the site working. And yes, working hard to sell ads, because that's what Yahoo! did. It gathered data and it served pages and it sold ads.
We watched Yahoo! get eclipsed in size and reach by Google... a more efficient and more profitable ad seller. They knew what you were searching for, so they could gather your data more efficiently and sell better ads.
These days companies know literally everything about you, your friends, your interests, and they use it all to sell ads.
When we sat down to start our own thing together three years ago we wanted to make something that wasn't just another ad clearinghouse. We wanted to spend our time building a service people wanted to use because it worked and saved them money and made their lives better in a small way. We knew that we could charge people directly if we could do all those things. We knew we could do what most people aim to do every day: avoid ads.
No one wakes up excited to see more advertising, no one goes to sleep thinking about the ads they'll see tomorrow. We know people go to sleep excited about who they chatted with that day (and disappointed about who they didn't). We want WhatsApp to be the product that keeps you awake... and that you reach for in the morning. No one jumps up from a nap and runs to see an advertisement.
Advertising isn't just the disruption of aesthetics, the insults to your intelligence and the interruption of your train of thought. At every company that sells ads, a significant portion of their engineering team spends their day tuning data mining, writing better code to collect all your personal data, upgrading the servers that hold all the data and making sure it's all being logged and collated and sliced and packaged and shipped out... And at the end of the day the result of it all is a slightly different advertising banner in your browser or on your mobile screen.
Remember, when advertising is involved you the user are the product.
At WhatsApp, our engineers spend all their time fixing bugs, adding new features and ironing out all the little intricacies in our task of bringing rich, affordable, reliable messaging to every phone in the world. That's our product and that's our passion. Your data isn't even in the picture. We are simply not interested in any of it.
When people ask us why we charge for WhatsApp, we say "Have you considered the alternative?"