Notes from the Google Webmaster Hangout on 26th July 2016.
Status Codes and Disavows are Not Permanent
404 and 410 do not have permanent effects. If you change them back to 200 then the pages will become indexed again, or redirects will start to pass PageRank.
Disavow also isn’t permanent, so if you remove the URLs from the disavow file they will start to pass PageRank, although this won’t happen until the URLs are recrawled.
Unlinked Landing Pages are Not Spam
Landing Pages which aren’t linked from the main site are not spam but may take longer to be crawled, and without links, Google will have trouble understanding the context, so John recommends they should be linked internally.
Google Uses Dates to Determine Fresh Content
Google may look at dates in an RSS feed or on a page to understand if it’s fresh content or evergreen content.
External Links do Add Contextual Information but Don't Improve Quality
External links do provide some additional information about the page, but having links themselves won’t improve the quality of a page.
Redirects Do Not Lose PageRank
Google say there is no PageRank loss for 301 or 302 redirects.
Mobile Pages should be Equivalent to Desktop
Desktop and mobile pages have to fulfil the same purpose and contain equivalent content, but there isn’t currently any ranking impact as Google is only really checking to see if the mobile page can be returned.
Don't Use Nofollow for PageRank Sculpting
John says it’s OK to use nofollow internally to prevent things like a calendar being crawled, but recommends against it for PageRank sculpting and says it won’t change anything.