As we walked back I spoke with Brett about some of the challenges faced when designing for a product with massive scale. Brett spoke about fringe cases; those situations where a small set of people have unique requirements that aren’t easily met by the product. In the regular world that small percent of users might consist of a couple hundred or thousand people. Given the relatively small impact, a lot of fringe cases get back burnered. At Facebook this cannot be done. In the world of a product at scale, 1% means tens of millions of people are having a poor experience with the product, and that’s a big problem. Brett explained that no matter how small the fringe case, the team needed to look into making the experience as positive as they could. Brett talked about how design teams have to consider the impacts that a broad range of network speeds and older mobile devices have on people’s experience. Given that Facebook is used worldwide, some locations won’t have the latest and greatest smartphones or high speed cellular networks. Those experiences need to be tested and accounted for on top of the best case scenarios. Brett added that these fringe cases add a unique challenge when designing new features that smaller scale products don’t have to worry about.

After arriving back at the team’s work area, I started chatting with Justin; one of the Facebook Search designers. I asked him what it was like working on a design that hundreds of millions of people would engage with. He explained that it could definitely be a little overwhelming if you let it get to you. He showed me one of the widgets he was making and said that it would typically get tens of millions of interactions on a good day in the US alone. Justin explained that making a design change that resulted in the usage numbers dropping a couple percentage points could definitely keep you up at night. He added that it reinforces the urge inside every designer to make the experience perfect at all times. If you didn’t, millions of people would potentially have a degraded experience. He then concluded that you need to move past the anxiety and do the job you’re capable of doing and know that sometimes things will ship to millions of people in an imperfect form; it’s just part of the job. The team learns and iterates change quickly, so if something doesn’t work as expected, it wouldn’t be long before it was fixed.