Indexing
In order for web pages to be included within search results, they must be in Google’s index. Search engine indexing is a complex topic and is dependent on a number of different factors. Our SEO Office Hours Notes on indexing cover a range of best practices and compile indexability advice Google has released in their Office Hours sessions to help ensure your website’s important pages are indexed by search engines.
Search Console Indexed URLs Counts Report Exact URLs in Sitemaps
Search Console indexed pages in Sitemaps uses exact URLs, so variations including www/non-www, trailing slash variations, etc, won’t be reported as indexed.
Canonical Tags Are Processed After Indexing
Canonicalised pages will be crawled, indexed, and then the canonical will be processed.
Noindex Pages are Indexed but Suppressed from SERPS
Noindex pages are still in the index, they are just suppressed from appearing in search results.
Background Images are Not Indexed
Images as Div background images will not be indexed in Google Images.
WWW Subdomain Should Not be "Parked"
If the www version of your domain is "parked", it might affect the indexing of the other versions of your domain.
Prevent Test Site Being Indexed with Canonical
John recommends using a canonical to the main site, although he says that it’s possible for both to be indexed.
Sites Inaccessible to the US Won’t Be Indexed
If a website can only be viewed in a country outside the US, Google will not be able to crawl and index the site, and it won’t rank anywhere.
New Pages Are Ranked Higher to Gather Signals
New pages are sometimes shown in search results and given an opportunity to perform, which may change when they gain more ranking signals.
Google Will Choose a Duplicate Page with the Shortest URL
URL paths doesn’t affect PageRank. However if there are 2 pages which are a duplicate, they will prefer the shorter URL.
Many to One 302 Redirects Will Be Treated as 404
URLs which are 302 to the home page on any large scale will probably be treated like a 404 and dropped from the index, and pagerank won’t be passed.