Google Uses Semantic Markup to Understand Importance of Highlighted Text
Google can use semantic markup such as bold, italics and headings to understand that highlighted words are especially important.
Meta Tags Can be Combined in One Tag
Meta tags can be combined rather than having to have each one on its own separate line e.g. content=notranslate nositelinkssearchbox.
Google Sees No Difference Between HTTP Header and HTML Section
Google can process content in the HTTP header and the static HTMLsection at the same time so there’s no benefit from adding tags in one or the other. This has no effect on crawl budget, for example.
Ensure Scripts in Head Don’t Close it Prematurely
John has seen instances of scripts inserting non-head elements into the head of a page, like iframes or divs, which could result in Googlebot missing hreflang links because it assumes the head has closed. This can be checked with Google’s Rich Results tool using ‘View Code’.
Header Tags are Optional
Header tags make it easier to understand content and group sections for ranking, but aren’t important for Google and don’t need to be used in a uniform way. CSS styles can also be used to highlight important content.
Use X-Frame Header to Stop Content Being Framed By Other Sites
X-Frame http header can be used to prevent browsers from allowing your content from being framed. Google also respects that and won’t index framed content.
Add Tag in Header to Specify Don’t Want Content Embedded in iframe
You can add a tag to the header of your page which will let browsers know that you don’t want content to be embeddable as an iframe
Links Within Primary Content Provide More Context but Less Weight than Sitewide Links
Googlebot differentiates between boilerplate content in headers, sidebars and footers for indexing. Links within the primary content provide more context than sitewide links, but sitewide links to pass more weight.
Dynamic Mobile Pages Take Precedence over Responsive
If you have a vary header which returns a different page for a mobile user agent, Google will use that as the mobile page instead of the responsive page.