
Years ago, when support for Schema meta tags was added to the WPSSO Core plugin, an add-on was created to express more complex Schema markup using JSON-LD encoding. At the time, most WordPress themes still offered Schema markup using RDFa and Microdata in their templates, and in those cases, adding JSON-LD markup automatically in the webpage would only create duplicate and confusing markup. Google was also one of the few (if not the only) search engine capable of reading JSON-LD markup, and still promoted the use of meta tags, RDFa, and Microdata (read by most social sites and other search engines at the time).