JSON is still rendered. It's not "render or send JSON", it's "render a string that contains formatted display output A, or a string that contains structured data B".
Facebook probably requires a lot of per-user effort true. A lot of sites (github for example) probably don't. It's probably limited to a couple areas of the header generally, or an A or B conditional render for an ownership page.
Facebook probably requires a lot of per-user effort true. A lot of sites (github for example) probably don't. It's probably limited to a couple areas of the header generally, or an A or B conditional render for an ownership page.
There's always exceptions to every rule though.