Personally IDGAF who sees or comments on my posts, but I understand how some users might feel different. Being able to restrict visibility of your content to people you follow would be a powerful feature for privacy, but you'd have to make sure that you only publish to relays that respect this policy.
Discussion
I would like to see a feature such as this that allows for a more private Nostr for those that need/want it. The feature would remind me of Google+ Circles.
nostr:npub1wmr34t36fy03m8hvgl96zl3znndyzyaqhwmwdtshwmtkg03fetaqhjg240 suggested recently that this could be done using MLS
i first heard that idea from Colby Serpa a year ago
Would be similar to the Facebook privacy feature where your content is only visible to your friends. The problem with Facebook is they took the granularity of their privacy features to a point where it's a tangled, disorganized web of settings that's difficult for some users to navigate.
Nostr clients should have a simple toggle switch restricting visibility to your follows, and relays should respect this policy by only serving your content up to requests signed by nsecs associated with the npubs on your follow list.