Google is testing a new search snippet feature titled Mentioned in.
This feature, which adds a new section to a search result snippet, lets the searcher expand and see the websites on which this site is also mentioned.
What it looks like. Here is a GIF of Mentioned in in action, provided by Brodie Clark:
Clicking on the down arrow will expand the feature to reveal the first two websites that are part of a carousel mentioning the page in the search snippet. You can slide through a carousel of more sites where this website is also mentioned.
Test variation. Google is also testing a version of Mentioned in without a dropdown, where you see the carousel by default. Here is a screenshot of that from Crystal Carter:
Why we care. Giving searchers information about other reputable websites that mention a site could increase trust in Google’s search results.
About this test. This seems to be a limited test. It reminds me of the goal Google had for the about this result feature. I wonder how many searchers will spend the time clicking the arrow to see more details, but that is why Google tests these features.