Drew, thanks for that link, I’ll give it a listen, and hope this photo is enough of a visual.

You’re confusing progressive enhancement with the ability to implement a given feature in a given browser.

I don’t think I am. I could have said that better. I was including the idea that a site need not look the same in all browsers in progressive enhancement. Though it’s not strictly part of progressive enhancement, but that notion is a reason the approach exists.

The squared and the rounded corners are equivalent. Everyone has the same content, functionality and care in their user experience. Just some people have corners one shape, and others another.

But where is that definition of equivalent coming from? Isn’t it one meaning among many? A particularly cautious designer may not see two buttons that look even slightly different as equivalent (or, may not agree that whatever Tom defines as equivalence is acceptable for their site).

And that’s where my question comes in. Because when we say that ‘web sites DO NOT need to look the same’, we are also saying that this designer is too cautious, picky, or even mistaken about the what comprises their organisation’s visual identity. Or, “No, the rounded edges on your buttons are not essential to your visual identity.”

Writing about progressive enhancement is not making such claims, and this question is veering away from the article.