Sort:  

Vegas, Baby! :)

for the links, if you're using markdown and not the raw HTML, use
[GitHub](http://github.com) which turns automatically into GitHub

How do I know I'm using this "markdown" feature?

It's the default choice when you're replying to comments or submitting a new post i think. You should be able to easily identify it as you see messages about it:

When writing a new post, if if markdown is active you will see the option to switch to the HTML Editor and then the other way around: