Personal social network

Each user should be able to create a personal social network based on the "follow" relation.

Each public user profile should have a follow/unfollow button that other users can press to add them in their personal social network.

Each user should have a section in their profile where they can see the list of followed users, also with the option to unfollow them. The visibility of this section is to be decided if:
a) Everybody sees the followed list of everybody, but only the owning user can edit it (by unfollowing people). This option is the Twitter approach (opened).
b) The list is a private section, visible and editable only by the owning user. This option would be a more private/enterprise oriented approach (closed).

Technically, it implies storing the list of followed users as an object (or multiple objects, one for each relation) in the user's profile page.