Plugin that would allow WordPress Authors to “follow” other Authors and query “Activity Info” from that

Just a plugin concept …

1. Add a form with a button to each user profile, post or wherever you want it named Follow or Unfollow. Show the button only if is_user_logged_in(). You may use a widget for the form.

2. On form submit update a user meta named follows for the user who clicked the button and another one named followers for … well … the user who just got a new follower. Use the user IDs as a serialized array (yes, ugly, I know). Or use a custom table, that might work better and faster.

3. Create a dashboard widget or a whole page where the access is restricted to users who can follow or be followed. Query for the user meta follows to get a list of all authors the current user has subscribed to and then query for the posts from these users.

4. Get the user meta followers and print a nice list of her followers.