LIKE IT or loathe it, Facebook has become an integral part of many people’s lives. In September, the site crossed a new milestone, reaching one billion monthly users.

But it’s not just membership, it’s activity. Every day half a billion people log in to Facebook. Each of these users has their own personalised news feed, with data drawn from their network of friends, and it’s refreshing from second to second.

Vice-president of engineering Mike Schroepfer’s job is to ensure the smooth running of Facebook. Large-scale outages are few and far between, so much so that when they do happen, it makes international news.

“Our goal is to make it not seem hard, so when you use the product it’s very seamless,” he says. “But there’s a lot of technical work behind it to make it scale.

“Everyone using the product gets a totally different experience, and even second by second it’s a different experience. As more people use Facebook, those interconnections get deeper, so there are more things happening in your network, updating more frequently.”

In 2008, Schroepfer moved from Mozilla, where he worked on the Firefox browser, to join the growing social network.

Back then, Facebook had only a fraction of the users it currently boasts. In December 2007, official figures put the site’s total at 58 million users.

“When I was at Mozilla I never thought I’d get the chance to work on something on a bigger scale because we had hundreds of millions of people using Firefox,” he says. “At the time I joined Facebook it was actually smaller in terms of users, less than 100 million. The thing that’s most fun about Facebook is the scale and reach of the products. That’s what drives me every day – the chance to work on something that so many people use.”

Everyone who starts in Facebook’s engineering team goes through a process known as bootcamp, a six-week introduction to the company and how it works.

Staff are encouraged to work on projects that they are not only good at, but that interest them, which Schroepfer believes is a large part in building a productive workforce.

“This isn’t a recreational activity. We’re trying to run a company and trying to build products. We have a very strong opinion of what we think is important and what’s in scope and out of scope for the company, and we try to communicate that very clearly to new hires and the company in every instant,” he says.

“Part of empowering people to make the choice is to trust them to make good choices based on those priorities.

“You’re trying to find that perfect intersection, which is something that’s really important to the company and that you’re really good at and really passionate about. Finding that intersection means that you’re going to be really good at your job and produce really great results.”

Facebook works on a philosophy of hacker culture, which means small teams that can work fast and respond rapidly, allowing the site to add new features at a fast pace.

“I’m humbled by the people I work with every day. The great joy of my job is that I always aim to be the least smart person in the room and to surround myself with people who are much more capable and intelligent than I am,” Schroepfer says.

“It’s incredibly humbling to do it, and I really love the people I work with. I love what I do and I believe deeply in the products we’re building. Hopefully, that comes through in the work that I do.”

Staff are also encouraged to take part in cross-company all-night coding events, known as hackathons. Some of the site’s major changes – timeline, chat and tagging in comments – came out of these sessions.

But while these tweaks and changes are aimed at making the Facebook experience better for users, they aren’t always seen that way.

The introduction of Timeline, for example, caused a storm of protest among users who wanted their profile to revert to the previous version. It’s a common scenario; the introduction of the “ticker” to the news feed last year caused similar consternation among some users.

“The end goal is always the same, which is to build a better product for people,” says Schroepfer. “The transition can sometimes be challenging for everyone, and it’s not something we enjoy when we see people upset by the transition, even if we know that the end point is a good one. We work hard to ease that as much as we can.”

The changes in how the site now works has had some unintended consequences for users, with tweaks to privacy settings leading some of them to unwittingly reveal information to audiences.

One allegation that Facebook had levelled at it in recent months was that the site was publishing old private messages on users’ walls. Facebook still insists, however, that there is no way that this could happen; rather, the company has repeatedly said it is old wall posts that are suddenly more visible thanks to the Timeline feature.

Balancing privacy and the desire to share content effectively is an ongoing battle for Schroepfer and his team. And that’s before you take into account the fact that spammers love the access the Facebook network gives them to people. There is a whole engineering team dedicated to developing technology to fight spammers, Schroepfer says, and it’s a round-the-clock job.

“It’s one of our best teams. It’s a 24/7 job, because there’s financial motivations for spamming people on Facebook,” he says. “What makes it an incredibly effective medium to communicate with your friends can also be used for other purposes.

Part of growing Facebook in recent years has required a new look at mobile. Facebook hasn’t just confined itself to the desktop. Mobile platforms have been both a bonus for the company and a hindrance.

Although more users are warming to the mobile version of the site, it was the popularity of mobile that caused some grumblings about revenues before the site introduced its own mobile advertising platform to its mobile app in recent weeks.

“I think there’s a lot of opportunity left in mobile because I think we’re just getting our feet and grounded in what we can build,” Schroepfer says.

Mobile users also log on more frequently, and can use the site as it was intended – sharing photos at the touch of a button.

The phenomenal growth of Facebook has led to the company opening its own data centres, the latest of which is in Sweden.

The location means that the cooling of the servers – usually with air conditioning – can be done in a more environmentally-friendly way, and can cut costs for the firm.

And the necessity for hardware has also led to the open hardware project. This was sparked by Facebook’s philosophy on open source.

When the social network was still a dorm-room project, it was built and run on open source software. It’s a philosophy that the company decided to apply to hardware too, partly from a desire to give something back to the industry.

“All we want to do is have more efficient, cheaper hardware. That’s the aim,” he says. “If we’re able to work with people on these designs, and standardise them and have more people manufacturing, developing and designing these things, it should mean more hardware, cheaper, for all of us. That’s a big advantage.”