Yostivanich

Much has been writ­ten on the big ticket changes in HTML5, like forms, seman­tics, and media, but infor­ma­tion on the less splashy changes is sparse. While global attrib­utes aren’t the most sexy change of HTML5, they are the change that you will be using over and over and over as you migrate to the new specification.

via HTML5 Glob­als and You – Net­tuts+. The most inter­est­ing attrib­utes (to me) con­textmenu and hid­den are cur­rently not usable by any browser engine.