You pasted the code into header or footer I think and it shows up on your page "google-site-verification: googlec00cf0114e0f0c50.html", I assume this is for your google analytics, I could be wrong but there is a place, Customize -> General, where you can paste the ID and it won't show up.
As you have seen creating a Facebook custom audience to your website is simple. Once you have gotten a decent traffic, Facebook pixel WordPress plugin will then prepare the custom audience for specified category for you to start promoting your articles. I trust that this Pixel Caffeine review has helped you. You can combine it with Google analytics and you will have perfect analytics in no time.
If anyone is using Woo ... check out Facebooks official plugin (Facebook for Woocommerce) that installs your pixel on your site and populates your Facebook page store with your products, and keeps them in sync ... you'd need to uninstall Pixel Caffeine or any other Pixel app first though. https://github.com/facebookincubator/facebook-for-woocommerce/