WhatsApp founder Jan Koum explains why he charged $1 for the product to intentionally slow growth

Charging for a consumer product. I remember in, like, you know, 2011 or whatever, people would still say, well, WhatsApp is never going to work because they charge a dollar and it's a viral app, and that's just going to kill it right there.

The thing about charging is actually very interesting. We used this lever to charge to actually slow our growth. And I know it sounds very counterintuitive because, like, well, why would you want to slow your growth? We wanted to slow our growth so we could better support our existing users, so we could build servers that don't crash, so that we could build product that doesn't drop messages, so that we could answer their customer support emails. A lot of people were telling us, what you're doing is wrong. You should really be growing as fast as you can. And we're like, no, no, no, no. We want to build the infrastructure first. And it's very similar, a little bit to Facebook. In early days, they were doing colleges only, and they weren't open to the entire world. We wanted to make sure that we have our existing users happy and that when people sign up, they have a great experience and that the app works and it's fast and the servers are up and running all the time. And I think that worked for us because we really were able to focus on the product.