I want to do some things that I think are easiest accomplished by allowing me to add arbitrary HTML to be embedded on all pages in the site. Specifically, I want to add meta tags to the top of the page so that it renders pretty-like in things like Twitter, and I want to add Piwik tracking to the bottom of the page.

So how do I do that?

I could write a whole new template for the site, but I suspect that there's a more modular approach that is advised. And if you have ideas of totally different ways do do this, do tell.

Thanks