Notes from the Google Webmaster Hangout on the 2nd of May, 2017.
Add Images to Sitemaps to Provide Google with More Information
Images can be added for each page of your site within your sitemap along with captions and alt-tags using special sitemap extensions.
Markup Which Isn't Used by Google in Search Result Doesn't Help
Google doesn’t take into account types of structured markup that aren’t used in search. The presence of that particular markup on your site won’t have any value for Google.
No Benefit is Gained For Optimising for Misspelled Search Terms
There is no additional benefit to be gained for optimising for misspelled keywords, and doing so may make site seem less professional to user. Google tries to recognise misspellings and will rank pages anyway. They also redirect users to the correct spelling.
Google Measures Site Quality Separately for Each Section of a Site
Google has moved to understanding sections of a site, and measuring quality for each section.
Company Schema Will Specify a Telephone Number to Appear in a Knowledge Panel
You can’t prevent a phone number showing up in a knowledge panel, but the Company page markup lets you specify which telephone number should appear.
Google Will Likely Move to Mobile-First Indexing in Batches
Google will likely provide guidance on when more changes can be expected. It’s probable they’ll move over batches of sites that work fine on mobile-first indexing first.
Sites should link related products together so that when these pages are crawled it’s easier for Google to branch out and understand the context of those pages.
Google Chooses the HTTPS Version of a Page if Both Exist
Google will choose the HTTPS version of a page instead of HTTP when both exist, but there is no change in ranking position.
Content is considered hidden when it is not visible at all. Content which fades in within a couple of seconds during a transition or is slightly transparent is likely to be indexed. You can test a transition using Fetch and Render.
Content Position in HTML Affects Context
You should make sure you keep related content together in the HTML, otherwise Google might not understand the context in which they are related.