Sunipeyk: As it says in the article:
“Wait a minute,” you may be saying, “I haven’t heard about widespread support for Shapes!” Indeed, you have not. They’re currently supported only in the WebKit/Blink family—Chrome, Safari, and Opera. But that’s no problem: in other browsers, the text will flow past the boxy floats the same way it always has.
(See previous comments for notes about
-webkit- prefixing for Safari.)