HTML5 - The nsfw element

Among the new semantic elements for section, footer, header and the like, HTML5 also adds an element that can contain any other element and describes it as Not Safe For Work (commonly abbreviated to “nsfw”).

Browsers can be configured by parents, workplace sysadmins never to show content marked as , thereby shielding faint-hearted people from obscenity and protecting employers from employees downloading things they shouldn’t.

It’s not just a presentational element, although it does carry with it the inherent CSS nsfw {display:none;}. The user agent is forbidden from downloading any of the resources contained within the element, if the browser’s setting is “on”.

http://html5doctor.com/the-nsfw-element/