The $19 billion deal to sell WhatsApp Inc. to Facebook Inc. started at Yahoo! Inc. more than five years ago, when Jan Koum became disillusioned at the way Internet companies were fixated on advertising.

He left Yahoo in 2007 with one of the company’s other engineers, Brian Acton, and started a company by 2009 that shuns advertising altogether. The strategy allowed them to concentrate on creating an easy-to-use messaging product instead of developing new ways to glean customer information for their marketing pitches, Koum said in a 2012 blog post.

“No one wakes up excited to see more advertising, no one goes to sleep thinking about the ads they’ll see tomorrow,” Koum said in the post. A hand-written note on the his desk reads: “No Ads! No Games! No Gimmicks!”

Their approach paid off. WhatsApp amassed 450 million monthly users -- twice as many as Twitter Inc. -- who send billions of messages a day. Yesterday, Facebook Chief Executive Officer Mark Zuckerberg bought their five-year-old company in the largest Internet deal since Time Warner’s $124 billion merger with AOL in 2001, a deal that will almost certainly make Koum and Acton billionaires several times over.

For Koum, 38, the windfall would stand in stark contrast to his years as a teenager, when his family relied on food stamps after emigrating from Ukraine. The experience of living in a country where phone lines were often tapped, instilled the importance of privacy in him, said Jim Goetz, a partner with Sequoia Capital Ltd., WhatsApp’s lone venture capital investor.

’Contrarian Approach’

WhatsApp doesn’t collect information like name, gender, address or age. Instead, users are approved after their phone numbers are authenticated.

“It’s a decidedly contrarian approach shaped by Jan’s experience growing up in a communist country with a secret police,” said Goetz in a blog post yesterday on Sequoia’s website. “Jan’s childhood made him appreciate communication that was not bugged or taped.”

Koum will join Facebook’s board of directors once the deal goes through. Facebook declined to make him or Acton available for an interview.

The partners are old enough to remember the first dot-com bust. Acton, 42, grew up in Michigan and was employee No. 44 at Yahoo, working on advertising, shopping and travel services, according to Wired. He invested during the boom and lost millions of dollars when the market imploded, according to Forbes.