AMP Sites can Also be the Mobile Version
You can reference an AMP site with both mobile rel alternate and rel AMP HTML, however the AMP page will become the primary version when Google moves to mobile-first indexing.
AMP Pages Don’t Affect Panda Unless they are Canonical
If you use AMP pages as your canonical pages, they will affect Panda, but if they are canonicalised to another page they won’t.
Use Fetch & Render using Smartphone User Agent, Mobile Friendly Testing Tool, and AMP Testing Tool to test for Mobile-first Indexing
The Fetch and Render tool set to use a smartphone user agent, the Mobile Friendly Testing Tool, and the AMP Testing Tool can be used to show you the content Google will use for the mobile-first index.
Separate AMP Pages Don’t Need Hreflang
If you have separate AMP pages, you don’t need to add hreflang. Implement in on the main desktop pages, the same as a dedicated mobile site.
No Plans for AMP to be Ranking Factor
John is not aware of any plans to make AMP a ranking factor.
AMP Doesn’t Impact Rankings
Implementing AMP is not a ranking factor at the moment. They are treated like any other mobile page.
There Is No Way to See Which AMP Pages Are Indexed in Google
AMP pages don’t appear in the index so site: queries won’t show them. Search console will only show you a total count, and a list of pages with problems. John suggests using analytics data to see pages with visits from Google to infer the pages are indexed.
Some Search Console Reports are Sampled
Some search console reports are based on a significant sample of the primary URLs, and won’t include every possible URL. e.g. Structured data and AMP reports.