[Phlow]

I think it's safe to say, at least from my view, that Bootstrap is the reason for it. Bootstrap made this format easy and clean, and it works well with mobile. Websites will look like this until someone comes out with the next thing that's easier and/or cleaner and/or works better in mobile and then a couple years later THAT will be the format you're seeing everywhere. I don't think this is a bad thing. At least it's clean and works well on mobile...

[flockonus]

Bootstrap didn't invent such websdesign, it was experimented with, learned and improved collectively. If anything, the library implemented these (almost) standards that were wildly used.

[mreiland]

He didn't say they invented it, he said they made it easy to do.

[JustSomeNobody]

Indeed. However, I always thought the idea of Bootstrap was to quickly get a prototype up, not become part of the final product.