Fix misunderstanding in tutorial

docs/tutorial.md

@@ -416,7 +416,7 @@ var CommentBox = React.createClass({
 });
 ```
 
-Here, `componentDidMount` is a method called automatically by React when a component is rendered. The key to dynamic updates is the call to `this.setState()`. We replace the old array of comments with the new one from the server and the UI automatically updates itself. Because of this reactivity, it is only a minor change to add live updates. We will use simple polling here but you could easily use WebSockets or other technologies.
+Here, `componentDidMount` is a method called automatically by React after a component is rendered for the first time. The key to dynamic updates is the call to `this.setState()`. We replace the old array of comments with the new one from the server and the UI automatically updates itself. Because of this reactivity, it is only a minor change to add live updates. We will use simple polling here but you could easily use WebSockets or other technologies.
 
 ```javascript{3,15,20-21,35}
 // tutorial14.js