This will come as no news to tech-savvy people, but when you open a webpage, you are running a metric shit-ton of code from all over the Internet.
And it’s from a lot companies, too. On the NYT alone, I get messages from various systems from google, amazon, facebook, doubleclick, moatads.com, brealtime.com.
Aside from the privacy and tracking aspects, it feels like a theft of resources, too. They’re using my CPU to do work that has nothing to do with rendering their page.