It's always nice to be able to understand where you may have the most reach when making content in community. This can help increase user engagement, provide valuable insights to forecast future content, and allow your team the ability to track growth.
Firstly, you'll want to be sure you have category following enabled, learn more HERE.
If you haven't already configured defaults on your site, there is a great post from one of our vanilla staff members that goes over Default Category Following & Notification Preferences.
While our product team is still scoping improvements to add in an API to allow for a full username list of real-time category followers, there is a workaround in the meantime to help you at least gauge exact counts and whom may be following a specific category.
There are currently two ways to currently pull metrics related to category following, which also can be termed subscription.
For the actual real time count following a specific category, this is available if we use a categoryID in the GET /categories API.
Example: When successfully running the API, you'll receive a response body.
In your response body, look for "countFollowers" , which will have a numeric value to give you an understanding of the total count of users following the categoryID
Our analytics chart pulls events in time of when a user actioned to follow a category.
Regarding analytics charts; you are able to get a list of users that followed (or unfollowed) a category in a certain time period, by means of our Subscriptions Change data stream.
The only kicker here is that analytics are events in time, so we do not retroactively delete records if a user is no longer following the category. This avenue is not ideal if you are looking for exact counts, as the user could be no longer following.
Example chart built to pull a list by username, category name, and change type:
Utilizing 'Filter > Change Type' we are able to select even other options if category follow is not your main metric you are looking to pull:
Change Type - the type of subscription change that occurred
Happy to help further if you have any questions. I hope this helped you learn a bit more about some tools available today!