User A needs to have the ability to block another user B. This will prevent User B's content from displaying in the User A newsfeed. It will also prevent User B from generating any notifications for User A (e.g. "commented on your post" @mentioned you,). It will also hide User A's content from User B's feed.
User A needs the ability to view a list of all Users that he has blocked. He needs the ability to unblock User B from that list.
User A needs to have the ability to block another user B. This will prevent User B's content from displaying in the User A newsfeed. It will also prevent User B from generating any notifications for User A (e.g. "commented on your post" @mentioned you,). It will also hide User A's content from User B's feed.
User A needs the ability to view a list of all Users that he has blocked. He needs the ability to unblock User B from that list.
User B should not know that User A blocked him.