I have few questions about Twitter, answer please?

[me]

1. How do you contact someone that isn't following you on Twitter?
2. When someone posts a tweet, and others reply to it can you see the reply?Or only the author of the tweet can see it?
3. When someone follow you do you receive any notification email?
4. How do you stop someone from following you?
5. If you set your tweets to private, does this mean no one can see it except the people that are following you and the people you follow?
How do I ask them to follow me if there isn't a message option???!

[Lexa Allnutt]

1. You ask to follow THEM.
2. You can see it if you are following them or if they're following you.
3. No you just get it on your Twitter
4. Go to their profile page
5. No only that ONE person can see it.

[NHK]

1. You just '@' them, or direct message them.
2. I'm pretty sure you will see the replies to someone else's tweet only if you are following that person. So if I write something on twitter, and five people respond to that tweet, the only way you will see it in your time line is if you are following me, or one of those five people.
3. Usually you receive notification in your email that so-and-so is following you if you have it in your settings for twitter to send that update to you.
4. You block them.
5. Only the people who follow you will be able to see your tweets if you set your profile to private