Google Will Use Other Canonicalization Factors If the Canonical Is Noindex
Google would receive conflicting signals if a canonical points to a noindex page. John suggested that Google would rely on other canonicalization factors in this scenario to decide which page should be indexed, such as internal links.
Only Use Sitemap Files Temporarily for Serving Removed URLs to be Deindexed
Sitemap files are a good temporary solution for getting Google to crawl and deindex lists of removed URLs quickly. However, make sure these sitemaps aren’t being served to Google for too long.
Submit Subdirectories to URL Removal Tool to Get Around Individual URL Limits
The URL Removal Tool limits the number of individual URLs that can be submitted to be removed per day. To get around this, you can submit subdirectories to get entire sections of content removed from Google’s index.
Number of Noindexed Pages Has No Effect on Rankings or Site Quality
Having a lot of noindexed pages doesn’t affect rankings or how Google perceives a site’s quality. For example, many sites need to noindex private content that requires a user to log in to access.
Many-to-one Redirects & Noindexed Pages Are Sometimes Treated as Soft 404s
Noindexed pages and too many pages that redirect to one URL can both be treated as soft 404 errors by Google. Having soft 404s doesn’t impact the perceived quality of your website, but these pages won’t be crawled as frequently or indexed at all.
Avoid Using Google Tag Manager to Implement Critical Tags Like Noindex
Google May Take Longer to Process Redirects For Noindexed Pages
Google crawls noindexed pages less frequently. If a redirect is set up for a noindexed page, Google may take longer to process this because it is being crawled less frequently.
Noindexing Some Pages with Hreflang Tags Won’t Affect Whole Configuration
It’s fine to noindex some pages within a set which have hreflang tags implemented. The noindexed URL will simply be removed from the set that Google uses, without affecting the other pages.
AMPs Which Canonicalise to Noindexed Pages Won’t be Valid
If a page is noindexed which is connected to an AMP equivalent, then the rel=amphtml link will be dropped too and the AMP won’t be valid. If the AMP is noindexed then it will be removed from the index and the traditional page will be kept.