MySQL can easily scale to well beyond the "500 users" unless each of those users puts an especially heavy burden on the data store. The scenario at hand is syn

MySQL can easily scale to well beyond the "500 users" unless each of those users puts an especially heavy burden on the data store. The scenario at hand is synchronizing recipes and that is not a heavy burden. Further, with a high-performance web framework, foregoing resilience (not recommended, but just for argument's sake) a single web-application instance should be able to handle a much larger number of users as well. But all of this isn't really relevant to the point made by the OP. He's just using these fictional data points as an illustration. Although I am personally in favor of using examples that are more representative of reality, I think we can mostly ignore the fictional data points to appreciate his point.