Sites like Hexbear source scripts from only one domain (hexbear.net). I like those sites.

Other sites loop in a few JavaScript libraries. They have a few domains asking for permissions. That's okay. A little lazy, but acceptable.

Then you have the corporate websites with, like, sixty JavaScript domains. Holy crap! What are scripts from facebook, pinterest, and amazon doing on this news article about jellyfish? And the website is perfectly functional with just a couple domains enabled.