An excellent list of shifts in the search industry, particularly around ranking signals, was posted by Search Engine Journal. The full link is here complete with some video explanations. It’s worth a browse. A summary is below.
Mobile-First
1. Sites Still Waiting to Be Switched over to Mobile-First Indexing Aren’t Necessarily Not Ready
2. After a Site Has Been Switched to Mobile-First Indexing
3. Make Sure Mobile Versions Aren’t Oversimplified & Include Relevant Content That Helps Google Understand the Page
Content
4. There Are No Differences in How Content in the HTML Is Treated Dependent on Whether It Is Visible or Not by Default
5. Use Rel=Canonical over Noindex for Duplicated Content
6. Google Can Index Duplicate Pages But Only Shows the Most Relevant One
7. Ensure That Scripts in the Page Header Don’t Close It Prematurely
8. Googlebot Doesn’t Use Cookies When It Returns to Crawl a Site
9. Crawl Budget Is Only an Issue for Large SitesGooglebot is able to crawl sites with “a couple hundred thousand pages” just fine.Only large sites with a higher volume of pages should be concerned about crawl budget issues.
Indexing
10. Serving a 410 Response Can Remove Pages from Google’s Index Quicker Than a 404
11. Linked Pages Blocked by Robots.txt Can Still be Indexed
12. Indexing Can Be Delayed If Canonical Tag Points to Redirect Instead of the Preferred Version
Javascript
13. Serving Critical JavaScript in the Head Can Block Rendering
14. Show Fully Rendered Pages to Googlebot Using Dynamic Rendering
15. There Will Be a Delay Between Initial Indexing & Rendering for the Foreseeable Future
Linking
16. PageRank Is Still Passed for Links That Aren’t Visible by Default
17. Bad Internal Linking on Mobile Can Affect How Pages Are Indexed & Ranked
18. Google Ignores Links Both Manually & Algorithmically
And more.