I have compiled a list of tools you might find helpful for testing structured data markup and rich snippet display (microdata, RDFa, RDFa Lite and JSON-LD)
Linkback protocols are an old breed. They were born in a time where MySpace, Wikipedia & WordPress had just been born, and Friendster was more popular than this new website called Facebook.
The latest linkback protocol, Webmention, is relatively recent though, as it became a W3C …