FIND OUT: Facebook founder Mark Zuckerberg’s No. 1 hiring rule

If you want to work for the social networking site-turned-multibillion dollar business co-founded by American computer programmer and entrepreneur Mark Zuckerberg, you have to be knowledgeable, skillful—and someone Zuckerberg would be willing to work for. Yes, work for.

This is the 30-year-old Facebook CEO's most important rule for hiring, as he revealed in Barcelona at the Mobile World Congress, where he spoke about the strides his Internet.org initiative has made in the developing world since he first announced its launch on year ago.

"I will only hire someone to work directly for me if I would work for that person. It's a pretty good test and I think this rule has served me pretty well," Zuckerberg said.

Moreover, he said that unlike other tech giants in Silicon Valley such as Google, he likes to keep his team as small as possible; that's why he personally makes sure that the people who will be hired as a part of Facebook has values aligned to the company's.

“Facebook is not a company for everyone in the world,” he said. The company's team is comprised of fewer than 10,000 people and this small number is a crucial part of Facebook's success, he further explained.

“[Facebook] serves more than a billion people around the world but our team has fewer than 10,000 people. It's only possible because of modern technology. Big companies get bloated."

According to a report on The Telegraph, one such person who passed Zuckerberg's hiring test is Facebook's chief operating officer Sheryl Sandberg who was handpicked for the role by the CEO himself.

The young entrepreneur considers Sandberg as a mentor and “someone who has been instrumental in building Facebook into a business and 'healthy organization.'”

In the said congress, Zuckerberg also made it clear that Facebook, the world's biggest social networking site, will remain focused on social media and the internet and has no other goals outside of it because connecting people globally is a "pretty broad" task in itself.

Zuckerberg's Internet.org initiative aims to help people in developing countries by providing them with internet access on their phones. — Bianca Rose Dabu/BM, GMA News