Hashtags are common on many social media platforms these days. As for Google’s own services, Google+ had hashtag support before it was turned off, and YouTube has had it for almost three years at this point. Discover is the latest Google service to experiment with hashtags, though it may seem a bit unnecessary.
The implementation in Discover is somewhat similar to how YouTube shows them, with a few hashtags appearing at the bottom of each map. In my opinion, these hashtags are kind of useless; the title is much better for telling me if I want to read the article or click on the video.
That said, if you want to see more content about the hashtag, you can tap to see more relevant articles and videos. If you type in the #FlatSixEngine hashtag, you’ll see more content that Google thinks you’ll like, but in reality I doubt people are looking for things to read or look like.
For now, these hashtags seem to be part of a fairly limited A / B test. I personally hope they do not become official because it only gives rubbish.