I imagine you're probably talking more about content, but you've uncovered a pet peeve of mine having more to do with the structure of web pages.
The original vision of html was to have this beautiful format that flows text and graphics elegantly over whatever space you give it. I remember thinking this is great! One day we will have pocket-sized displays and the web is already future-proofed to work seamlessly in that world.
Then fast-forward to smart phones. By now, web pages were so rigidly formatted that they had to design special mobile versions of every site.