I recently discovered a really great website: firebase.com. It will store data for your applications, enabling you to write really awesome programs (such as multi-player games) using it - and the Development account (which I used) is free!
To communicate with the API, I had to learn HTML. I also learned some CSS and jQuery to make things easier. Then I wrote a live chat app using my knowledge.
In the app, you can use HTML to format your comments. At one point I allowed use of the <script> tag, but after users abused it I disabled it. I also added a couple of new tags: <console> and <incode> You can post a comment by either clicking "Post Comment" or pressing the Alt key on your keyboard.
