A Featured Snippet Can Source its Text & Image from Different Sites
Images in featured snippets are sometimes taken from a different website to the one where the text snippet was taken from.
Quality is Assessed Differently for Featured Snippets & Rich Snippets
Quality is assessed in a different way for featured snippets and rich snippets. So your site can be showing for rich snippets but not featured snippets, and the other way around.
Googlebot Can Recognise Faceted Navigation & Slow Down Crawling
Googlebot understands URL strucures well and can recognise faceted navigation and will slow down when it realises where the primary content is and where it has strayed from that. This is aided by GSC parameter handling.
Separate Mobile Sites Need to be Crawlable at the Same Speed as Desktop
Separate mobile sites need to be able to be crawled at the same speed as on desktop so if your separate mobile site is hosted on a slower server then this will affect Google’s ability to rank it.
Overall Site Quality is Only Judged by Looking at Indexed Pages
Google only looks at the indexed pages when assessing overall site quality, so noindexed pages won’t reduce your site’s quality.
Use Canonicalisation Instead of Noindex for Duplicate Content
John recommends using rel=canonical instead of noindex in order to deal with duplicate content in the best way. This way the signals from both page versions can be combined rather than dropping all the signals from the noindexed page.
Make Sure Content is Equivalent for Long Term A/B Testing
Long term A/B testing doesn’t cause any issues for Google as the content is equivalent between what the user and Googlebot see. Short term A/B testing with significant content changes don’t cause issues.
Google Adwords Uses Different Algorithms to Organic Search
Google Adwords uses different algorithms to the organic search algorithms, so if you see your site appearing for certain topics in Keyword Planner this isn’t indicative of how your site is seen for search.
Provide Desktop Version to Mobile User Agent if There is No Mobile Equivalent
For mobile-first indexing, if there is no mobile version of a page it should not 404 for the mobile user agent. Instead the desktop version should be made available for Googlebot Smartphone.
Googlebot Can Handle Two Versions of Navigation for Responsive
Having two separate sets of navigation coded in the HTML for desktop and mobile on responsive sites doesn’t cause an issue for Googlebot.
Fetch as Google Doesn’t Make Any Changes to the Index
Fetch as Google only requests the page so it can’t be used to bring Google’s attention to an updated status code, for example. In order to affect the index you need to use Submit to Index where additional processing will be done.
The Site Move Setting Takes a While to Update in Search Console
The setting for a site move sometimes sticks in Search Console for a while even if Google has recognised and processed the migration. Check Google Analytics to make sure traffic is going to your new site correctly.
Desktop Search Results Will be Generated from Mobile Pages with Mobile-first
Desktop users will see relevant desktop pages, but the search results will be generated from content crawled from mobile pages after mobile-first indexing. Desktop ranking will be impacted if you have reduced content on your mobile pages as that is where Google will be sourcing content from.