Notes from the Google Webmaster Hangouts on the 23rd of September, 2016.
Limit Indexing of Internal Search Pages
You can index internal search results pages, provided they are generally useful to users and are limited to specific terms.
Only Use Nofollow on Filtered Pages to Prevent Excessive Crawling
Add a nofollow on links to filtered, sorted and paginated results pages to prevent excessive crawling.
Cross Domain Sitemaps Work if Both Domains Verified in Search Console
You can submit Sitemaps with URLs on a different domain if both of the site are verified in the Search Console account.
Use Noindex for Returning Pages
If a page has been permanently removed by responding with an error, if it comes back, the page will be treated like a new page, unlike a noindex.
Don’t use Robots.txt Disallow Except to Prevent Server Performance Issues
John recommends against using robots.txt disallow to prevent facet URLs from being crawled as they may still be indexed. Instead allow them to be crawled and use a noindex or canonical tag, unless they are causing a server performance issue.
Don’t Use Nofollow on Footer Links
John recommends against using nofollow on footer links.