What is Facebook's secret to keeping the world's largest user base content? Sticking to well-proven software design principles, one study has concluded.
University of Washington graduate student, Parmit Chilana, worked as an intern at the social networking giant last year, and, during her time there, interviewed Facebook engineers and design specialists to learn about how they build and deploy new features for the service. Chilana discussed her report, which she co-authored with other researchers at the University of Washington and Facebook itself, at the Association for Computing Machinery's Conference on Human Factors in Computing Systems, being held this week in Austin, Texas.
Facebook has an audience that would make user bases of even the largest software products seem small in comparison, Chilana explained. As of latest count, the social networking service has over 845 million users. And it is an audience as diverse as it large: Facebook supports over 70 different languages. About 80 percent of its users live outside of the U.S. and Canada.
"Even if only 1 percent of the users were dissatisfied, that would still represent close to 10 million users," Chilana said. "Most software companies don't even have a user base of 10 million users. So you can imagine the impact of [Facebook's] design choices can be enormous."
While its users may grumble about periodic privacy infractions or buggy new features, Facebook has largely been able to continue to increase its user base and keep them involved. About 50 percent of its users log on every day, and interact with more than 900 million objects that Facebook stores on their behalf.
Chilana sought to identify what perceptions those in charge of Facebook's user interface held about what makes for a successful user interface. She interviewed 17 Facebook employees -- software engineers, product designers and product managers. She queried them about the decisions they had to make when launching a new product or feature and asked how decision choices fit in with the company's business priorities.
Chilana's work "is one of the very first studies of Facebook's [design] process," said Wayne Lutters, a computer science associate professor at the University of Maryland Baltimore County, who moderated Chilana's talk. Only recently has the company "slowly started opening its doors to outsiders," wishing to learn more about its development process, he said.
As a baseline, Chilana used the generally agreed upon principles of good software user interface design, as espoused by John Gould and Clayton Lewis in a 1985 paper "Designing for usability: key principles and what designers think." Gould and Lewis stressed iterative design, a focus on user testing and user-focused design in general.
While many product designers tend not to be aware of such principles, Facebook relies heavily on such ideas, Chilana found. "Over half the interview participants explicitly identified user experience as a key factor in driving design on Facebook," Chilana said.
Facebook also values iteration. One engineer told Chilana that the company "will just try to get something out there, make sure it is reasonable and then iterate on the design based on how people are using it," she said. "Design is hard," another designer told her. "Just doing our best with very smart people, we screw up plenty."
This approach is not always easy given the size and variety of Facebook's user base. One engineer told Chilana that "once you get away from the core features, it is not necessarily obvious that there is a magic way that a feature could work in a way that everyone can find value in it," she said. Engineers often have to design for the least common denominator, she said. Many proposed advance features don't get implemented because the adoption rate would be too small to make the work worthwhile.
Engineers cannot simply rely on intuition. Early on in the company's history, Facebook engineers added many features on the premise that if they thought the feature would be cool or useful, so too would the users. The company is slowly moving away from this mindset, Chilana said. New features, such as a photo upload button, must be equally intuitive to a 90-year-old Mongolian grandmother as to a 14-year-old Brazilian soccer player, one engineer told Chilana.
Even with user satisfaction in mind, Facebook designers are not afraid of implementing a cutting-edge feature that fulfills the company's long-term vision of what a futuristic social-networking site should be like, even if it causes short-term dissatisfaction with users. When Facebook introduced the Timeline format last year, for instance, some users complained that it was clunky and difficult to use.
One engineer praised the company for not being afraid of making changes even if it causes some dissatisfaction. In some cases, such as the controversial Timeline, Facebook will give users the option to update to a new feature before rolling it out across the entire site. This works to minimize the disruption caused by the new feature, as well as giving the company engineers more time to tweak the design.
Despite its size, Facebook faces the "same frustrations" that other organizations do when trying to design good interfaces for their users, Lutters said. "It's a very familiar tale, even if the stakes are much higher."
"It's a positive affirmation that they are doing the things everyone is else is doing to stay current, relevant and focused," Lutters said. "If there is a secret sauce, she wasn't able to uncover it."