@cackhanded is right. class is used on visible content. Thus HTML authors & designers learn & use class already. @snookca @Malarkey, #microformats prefer simplicity, familiarity, & learnability. For #microformats2, we aimed to make them even simpler than classic #microformats, as well as more compatible with existing class values. In addition the data-* attributes are meant for private page-specific meaning, and explicitly not for shared or cross-site data. http://microformats.org/wiki/HTML5#data_attributes There were attempts to use new attributes in HTML instead, with both RDFa and microdata, and the result was more complex designs using *multiple* new attributes, each, which were more work to learn, and harder for authors to use: https://indiewebcamp.com/irc/2014-06-21/line/1403415993000 And as @cackhanded says, easy parsing too, especially with the microformats2 parsing specification and now numerous open source libraries in nearly every language: http://microformats.org/wiki/microformats2#Parsers

@cackhanded is right. class is used on visible content.
Thus HTML authors & designers learn & use class already.

@snookca @Malarkey, #microformats prefer simplicity, familiarity, & learnability.

For #microformats2, we aimed to make them even simpler than classic #microformats, as well as more compatible with existing class values.

In addition the data-* attributes are meant for private page-specific meaning, and explicitly not for shared or cross-site data.

http://microformats.org/wiki/HTML5#data_attributes

There were attempts to use new attributes in HTML instead, with both RDFa and microdata, and the result was more complex designs using *multiple* new attributes, each, which were more work to learn, and harder for authors to use:

https://indiewebcamp.com/irc/2014-06-21/line/1403415993000

And as @cackhanded says, easy parsing too, especially with the microformats2 parsing specification and now numerous open source libraries in nearly every language:

http://microformats.org/wiki/microformats2#Parsers