Notes from the Google Webmaster Hangout on the 14th of December 2018.
GSC Incorrectly Flags Pages as Not Mobile-friendly if it Doesn't Have Capacity to Fetch CSS
Search Console can incorrectly flag pages as not being mobile-friendly if the site’s server is too slow for Google to fetch the CSS files for these pages. John said that you may see individual pages that flag this error and they may fluctuate over time, but it isn’t an issue if you can see that the page is mobile-friendly.
Use Mobile-friendly Test & Googlebot User Agent in Browser to Check For Rendering Issues
Use Structured Data to Markup & Display Social Profiles in Knowledge Panel
Use structured data to provide Google with details about a site’s social media profiles. It may take some time before the social media profiles are displayed in the Knowledge panel, as Google needs to ensure that the right profiles are being linked to.
Crawl Budget Updates Based on Changes Made to Site
A site’s crawl budget changes a lot over time, as Google’s algorithms react quickly to changes made to a website. For example, if a new CMS is launched incorrectly with no caching and it’s slow, then Googlebot will likely slow down crawling over the next couple of days so that the server isn’t overloaded.
Provide Last Modified Date in Content & Structured Data For Rich Snippet
Providing the last modified date within the page’s content and as structured data makes it easier for Google to show this as a rich snippet in the SERPS, especially if both dates match.
Use Flexible Sampling or First Click Free to Allow Google to Crawl Content Behind Paywall
For pages with a single sign-on interstitial or behind a paywall, John recommends implementing flexible sampling or a first-click free approach so that Googlebot can crawl these pages.
Place Videos High up on Page For Better Chance of Being Displayed in SERPs
John recommends placing videos fairly high up on a page to help Google understand it is a video landing page.