Facebook has gone from a small startup to a major player in our daily lives — and global geopolitics. DW answers five basic questions about the controversial tech titan.

What?

It started life as Facemash — a site to rate fellow students as "hot" or "not" — in a Harvard University dormitory room in 2003. That quickly evolved into something similar to its current form: thefacebook.com. At first, the network was a way for Harvard students to socialize online. But it quickly spread to other universities, then high schools, and then the general public as it gained new features. Users could post content on other profiles and tag their friends in photos.

When?

Facebook's timeline is a tale of rapid growth. At the end of 2004 it already had a million registered users. By 2008 it had 100 million — and four years after that it had surpassed a billion. Now, with an estimated 2.2 billion active monthly users, Facebook is a part of life for more than a quarter of the world's population.

Who?

Facebook CEO Mark Zuckerberg is the fifth-richest person in the world. The 33 year old former psychology student, easily recognizable in his uniform of t-shirt-and jeans, has become synonymous with the social network. But other faces were involved in getting it off the ground. Together with three fellow Harvard students at the time — Dustin Moskovitz, Chris Hughes and Eduardo Saverin Tyler — Zuckerberg cofounded Facebook. He was later sued by former business partners, Cameron and Tyler Winkelvoss, for allegedly stealing their idea. The story inspired the 2010 film The Social Network.

Today Facebook is run by CEO Zuckerberg, his chief operating officer Sheryl Sandberg, and a handful of business people with technical backgrounds. The company employs about 25,000 employees in dozens of countries across the world.

How much?

The first outside investment in the company came from Paypal founder Peter Thiel, who bought a 10-percent stake in the company for half a billion dollars when Facebook was still getting off the ground in 2004. Facebook is free to use, but the company makes money through advertising and online marketing, which it can target at users based on their interests. Facebook's total revenue in 2017 was about $40 billion (€33 billion).

Why?

Facebook claims its purpose is to make the world more open and transparent. Its founding principles identify three constraints to achieving this: law, technology, and evolving social norms.

In a Facebook post at the start of the year, Zuckerberg announced his challenge for the year was to "fix Facebook." He wrote: "The world feels anxious and divided, and Facebook has a lot of work to do — whether it's protecting our community from abuse and hate, defending against interference by nation states, or making sure that time spent on Facebook is time well spent."