Whether you realize it or not, if you've built a rich web application in Ember.js, and you're sending data between clients and a server, you've build a distributed system. This talk will discuss the challenges of building such a system, specifically the challenges related to preserving consistency when dealing with concurrent actors. We will begin with a primer on the various types of consistency, covering topics such as eventual consistency and causal consistency, and then move on to discuss recent industrial and academic research that aims to solve some of these problems without synchronization, specifically discussing operational transformations and convergent and commutative replicated data types.