Restricting who can see you is only possible if you don't allow anonymous access. Otherwise, to see posts from the person you're stalking, just log out and try again. However, requiring people to register just to see content is a huge barrier to adoption. So you can't do that by default; at best, you can give people the ability to make their own posts non-public, but in a system with threaded replies and decentralized distribution, you have to figure out what that even means. On Usenet, for example, you might not have seen that post from someone you don't like, but you'd still see the parts that were quoted in replies.
no subject
Restricting who can see you is only possible if you don't allow anonymous access. Otherwise, to see posts from the person you're stalking, just log out and try again. However, requiring people to register just to see content is a huge barrier to adoption. So you can't do that by default; at best, you can give people the ability to make their own posts non-public, but in a system with threaded replies and decentralized distribution, you have to figure out what that even means. On Usenet, for example, you might not have seen that post from someone you don't like, but you'd still see the parts that were quoted in replies.