Having HTTP Version in Google Listings or Snippets Can Drive Impressions Even After HTTPS Migration
If you’re seeing impressions and clicks for the HTTP version of your site after migrating to HTTPS, this could be because the HTTP version is linked to somewhere externally in a knowledge box or your Google My Business listing, for example.
Relevance is the Primary Factor For Showing Featured Snippets
The main factor for deciding what to show in featured snippets is relevance. Things like authority aren’t taken into account.
Quality is Assessed Differently for Featured Snippets & Rich Snippets
Quality is assessed in a different way for featured snippets and rich snippets. So your site can be showing for rich snippets but not featured snippets, and the other way around.
A Featured Snippet Can Source its Text & Image from Different Sites
Images in featured snippets are sometimes taken from a different website to the one where the text snippet was taken from.
Secondary Content’ Won’t be Used for Snippets
Content not instantly visible is treated as secondary content and wouldn’t be used for snippets until Google shifts to mobile first indexing