With the BuddyPress Hashtag plugin You can follow hashtags on your BuddyPress Community site to stay connected with interests you care about. Navigate to BuddyPress Prfille > settings > Hashtag, and add any hashtag (example: #summit) you want to follow.
Once you follow a hashtag, you’ll see activity related to that hashtag appear in the sitewide activity feed and also on the profile feed under the Followed Hashtag tab.
Sitewide Activity Page
Profile Feed
