Right from the frontpage (check the links over there):
"Who uses HTML5 Boilerplate?
Google, Microsoft, NASA, Nike, Barack Obama, Mercedes-Benz, ITV News, BAE Systems, Creative Commons, Australia Post, Entertainment Weekly, Racing Green, and many more."
> You usually won't know a web page is actually using H5BP, especially without looking at the source.
One of the ways to know, before the new release which sadly kills it, was that many sites didn't customize the default hot pink text-selection background color.
Select text and get hot pink? You knew it was the boilerplate.
"Who uses HTML5 Boilerplate?
Google, Microsoft, NASA, Nike, Barack Obama, Mercedes-Benz, ITV News, BAE Systems, Creative Commons, Australia Post, Entertainment Weekly, Racing Green, and many more."