Allow users to choose blog categories when first sign up on the community platform by pulling information from category list created by user. Give the site manager the right to allow this action upon user activation so users can choose what blog post they would like to be notified on. When you release the Buddyboss membership update allow the site manager top to tie subscription to category groups or individual categories, allow site manger to group categories by via by organizing categories by creating category groups and adding categories to category groups to all for better group choices by users or users can choose individual categories according to their subscription. Site manager should have the rights to choose what categories or category groups can be a part of what subscription they have created.