A clever idea from Michael Donohoe: pit websites against each other in a performance battle! Donohoe is a long-time newsroom guy, so this is specifically about article pages for major publications.
Lets state the obvious, this is an imperfect and evolving measure and the goal is to foster discussion and rivalry in making our pages better, faster, and lighter. Bear in mind this was built as an internal tool at Hearst Newspapers to track changes as we rollout our new Article template on mobile for SFGate and eventually all sites (SF Chronicle, Houston Chronicle, Times Union, etc).
Developers, designers, and product need to talk more on how to achieve this. A 1,700 word article might weigh 10KB but by the time you load HTML, JS, CSS, images, 3rd-parties, and ads, it can range between 2MB to 8MB depending on the web site. Bear in mind, the first Harry Potter ebook is 1.1MB and that includes cover art.