This document discusses data binding in AngularJS. It explains what data binding is, the difference between one-time and two-way binding, and how data binding works through dirty checking. Data binding connects the UI and business logic by allowing changes in the model to be reflected in the view and vice versa. One-time binding only updates the view once from the controller value, reducing the number of watchers and improving performance compared to two-way binding. The document also provides examples of data binding and takes questions.