Making servers for online games becomes challenging because of a global audience and a potentially unlimited user base (Not quite). If a game suddenly becomes popular (and you never know when), it can go rom a few hundred thousand daily active users (DAU) to millions in a few weeks.
Some companies are caught by surprise and have to work day and night to save the business and do architectural changes under firefighting conditions. King on the other hand is a ten year old company with plenty of experience and did it's best to prepare for the stampede a potential hit game can mean on the social and mobile game market.
Although firefighting almost becomes the norm when dealing with high traffic, there are some architectural decisions that turned out to be fortunate in terms of being able scale horizontally and be able to analyse performance problems in a controlled fashion. A lot of it is related to how data is stored and accessed. King now almost routinely launches games that attract millions of DAUs within a couple of weeks and in this talk we want to share what we believe it is that makes this possible.