Sequoia Capital gives an insight on why Facebook bought WhatsApp.

Two numbers stand out for me.

One.

WhatsApp has one focus: messaging.

This discipline is reflected in WhatsApp’s unconventional approach to business. After one year of free use, the service costs $1 per year — with no SMS charges. This can save users trapped in expensive data plans up to $150 per year.

And charges only $1 per year.

It’s easy to take this novel model for granted. When we first partnered with WhatsApp in January 2011, it had more than a dozen direct competitors, and all were supported by advertising. (In Botswana alone there were 16 social messaging apps). Jan and Brian ignored conventional wisdom. Rather than target users with ads — an approach they had grown to dislike during their time at Yahoo — they chose the opposite tack and charged a dollar for a product that is based on knowing as little about you as possible. WhatsApp does not collect personal information like your name, gender, address, or age. Registration is authenticated using a phone number, a significant innovation that eliminates the frustration of remembering a username and password. Once delivered, messages are deleted from WhatsApp’s servers.

Zero.

Rather than invest in marketing, they let the service sell itself.

There may be no greater testament to the viral nature of WhatsApp than the fact that the company has accomplished all this without investing a penny in marketing. Unlike their smaller competitors, it hasn’t spent anything on user acquisition. The company doesn’t even employ a marketer or PR person. Yet like the world’s greatest brands, it’s created a strong emotional connection with consumers. All of WhatsApp’s growth has come from happy customers encouraging their friends to try the service.

I find their success through such a minimalist approach an inspiration.