[callahad]

AMP is not a subset of HTML; AMP replaces many HTML tags with its own proprietary custom elements, like amp-img, while banning normal, standards compliant img tags. It also has a bunch of vendor-specific tags, like amp-instagram and amp-twitter (but no amp-flickr or amp-vk), so Google gets to be a bit of a kingmaker in what content gets bespoke tags. Ads have to go through amp-ad, where Google also controls which advertisers are allowed on AMP pages, so you're allowed to show ads from the Doubleclick network, but not from The Deck or Carbon networks. Oh, and Google rehosts your AMP pages, so you don't even get to see traffic data to your own content.

This is a massive landgrab by Google that only incidentally solves a real performance problem on the web.