Recently we made an ExtraContent Stacks Plugin that you add to your Stacks Library. This allows you to use ExtraContent in your ExtraContent enabled themes without having to use code or snippets.
Now, in the comfort of the Stacks user interface, you can control which ExtraContent area gets occupied. Of course, building your ExtraContent areas in Stacks means that you have the full features of this powerful layout tool at your finger tips.
Check it out, it's VERY cool.