Why Semantic Markup Never Spread
HTML gives documents light structure. CSS adds presentation. The deeper structure that would let machines understand a book, an address, or an event has remained rare because adding it is extra work. Joel Spolsky and the team behind the Block Protocol argue that the only way semantic markup will become common is if the cost of adding it drops to zero or below.
Blocks That Carry Meaning
The protocol defines a standard way for any editor to embed a block and for any developer to publish a block. A book block, for example, can present a cover image and title to human readers while embedding the corresponding schema.org data for machines. An address block can render a map or a plain text line and still expose the structured location underneath. Because the protocol is open, the same block can appear inside WordPress, a note-taking app, or any future editor that implements the embedding interface.
WordPress as the First Large Host
WordPress still powers a large fraction of the public web. A free plugin turns any WordPress site into a host for Block Protocol blocks. Authors insert them the same way they insert native Gutenberg blocks. Developers who want to add a custom block no longer need to write PHP or package a traditional plugin; they publish once to the protocol and the block becomes available everywhere the plugin is installed.
The project has moved through several specification versions. Early drafts focused on the core embedding contract and a type system that lets blocks declare the shape of their data. The practical goal remains the same: make structured, machine-readable content the default rather than an afterthought.
Whether the broader ecosystem adopts the protocol will depend on how many editors choose to support it and how many useful blocks appear. The bet is that once the friction disappears, both sides will find reasons to participate.