The notion of "following" is not intrinsic to #nostr. Certain clients implement the NIP-02 protocol as a way to implement twitter-like following; but that's just a client thing. More-speech, for example, has no concept of following. If you want to read someone's notes in more-speech, you add them to a tab. This does not involve NIP-02. Indeed, you can add all kinds of things to tabs, like threads, regular-expressions, and users. What's more, adding an author to a tab is not announced publicly.
More-speech uses NIP-02 for the concept of "Trust". If I trust that a certain npub is really who they say they are, then I can "trust" them and give them a pet name. This is then broadcast publicly in a NIP-02 contact list. There is a special tab in more-speech for trusted users. It contains all the notes sent by those users.
From: (fmar) at 07/16 07:23
> Which nostr clients are notifying that somebody follow/unfollowed you? I see primal.net webapp does this, but it is the first one I noticed. Amethyst certainly doesn't. Does damus or anyother in ios? nostr:npub1gcxzte5zlkncx26j68ez60fzkvtkm9e0vrwdcvsjakxf9mu9qewqlfnj5z nostr:npub1xtscya34g58tk0z605fvr788k263gsu6cy9x0mhnm87echrgufzsevkk5s nostr:npub16c0nh3dnadzqpm76uctf5hqhe2lny344zsmpm6feee9p5rdxaa9q586nvr
CC: #[4]
CC: #[5]
CC: #[6]