Notes from the Google Webmaster Hangout on the 17th of October, 2017.
Google Does Some Scrolling on Pages
Google does some scrolling on a page to make that there is nothing that would otherwise be missed.
Prevent InfiniteScroll Content Being Indexed by Blocking Onscroll Script with Robots.txt
If you need to prevent onscroll loaded content from being indexed, as with pages using infinitescroll, put the script that’s executed with the onscroll behind a robots.txt block.
Google Mainly Uses GET Request For Normal Crawling & Indexing
AJAX Crawling With Escaped Fragment URLs is a Deprecated Set up
Using AJAX crawling set up with escaped fragment URLs is a deprecated set up. At some point Google will be turning off support for escaped fragment URLs and will only crawl and render the hashbang URLs themselves.
Serve 503s When Site Down For Maintenance
Serve 503 response codes (temporarily unavailable) instead of 404 errors when site is down for maintenance.
Header, Footer & Sidebar Links Seen in the Same Way by Google
Header, footer and sidebar links are basically seen in the same way. Google differentiates between primary content and the boilerplate (everything around it).
Fine to Make Large Scale Site Changes at Same Time But Cause Bigger SERP Fluctuations Than Phased Changes
No problem with making large scale changes to the content on a site all at once, but this will result in larger SERP fluctuations. Spreading content changes over time will result in smaller fluctuations over a longer period of time.
Google Could Already be Indexing Mobile Version For Small Number of Sites
John says Mobile-first Indexing is still in the experimental stage but it’s possible that Google are already indexing the mobile version for individual sites but for a very small quantity.