When you block a user, they won’t be able to view your tweets, message you, or follow you. They also won’t get a notification that they’ve been blocked, but if they visit your profile page, they will notice that they can’t see your tweets. You can’t follow someone you’ve blocked, and you won’t see their tweets in your timeline, either. To see accounts you’ve blocked, and unblock them if needed, go to the More button again, then navigate through Settings and privacy > Privacy and safety > Blocked accounts. Or, if you’re looking for a shortcut, just click here.