Google has said that it wants to bring the benefits of its AMP specification to sites that stick with Web standards, offering them the same prominent search positioning that it currently only gives to sites using its proprietary tech.
The purpose of these restrictions is to ensure that AMP pages are small, simple to render, and consistent. Any resources that the pages depend on come from Google's cache, and they're loaded asynchronously to ensure that the textual content of a page is never forced to wait for other assets to load. The caching is designed such that Google can embed AMP content in other contexts—for example, the "Top Stories" feature on Google's search listings—and do so in such a way as to not confuse site analytics and advertising. Google developed AMP in response to other proprietary tech such as Apple News and Facebook's Instant Articles.
The features of AMP aren't undesirable in and of themselves. Web performance, especially on mobile platforms, matters, and a set of best practice rules to follow to achieve good performance is no bad thing. Being able to tie performance and clean code to specific benefits, such as a prominent Google placement, might even be useful for developers wanting to persuade their bosses that dropping auto-playing video and streamlining their code are things worth investing in.
But AMP isn't standard, and many feel that Google is strong-arming sites into supporting its proprietary format, diminishing the open Web in favor of something Google-proprietary. Those prime listings in Top Stories are only available to those who provide AMP versions of their sites. Want to keep things strictly standard? Then no prominent positioning for you.
Google's caching system is also criticized; currently, every AMP page is served from a google.com URL, obscuring the original URL and hence the connection to the site that actually developed the content. Google has announced a plan to fix the URL issue, but as things stand right now, it's a big sore point.
Opponents of AMP also argue that AMP is unnecessary; it's possible to build fast Web content simply by not doing things that are slow; it's one thing for Google to prioritize fast content, but that should be open to any content that happens to load and render quickly, not content that jumps through special Google hoops.
In this week's announcement, Google has said that it's not going to stop developing AMP. However, it's going to offer features like the same prominent search positioning to sites built using standard HTML. Exactly which standard HTML and how it should be used, well… that's still to be determined. The company has said that it's going to use Web Packaging, a spec for bundling related Web resources together that'll eventually be on the standards track, but other specifics aren't yet forthcoming. Neither is a timeline for when the AMP benefits will be made available to non-AMP, open content. Nor do we know, yet, if other AMP benefits, such as integration into Gmail, will be offered to this non-AMP content.
As such, the new announcement hasn't quelled the complaints. It's a positive step, but without a timeline and specifics, it's impossible to know exactly how Google will position AMP versus open standards.