When you reply to people on twitter do they see it?

like how do famous people see what there fans say to them on twitter if there not following them?

just wondering whether people can see my tweets even thought my twitter is protected,, i don't want my tweets to be seen by everyone unless I use the hashtag.

For example, if I tweet a celebrity but they're not following me, can they see my tweet though it's private (but I put "@" and then their username?

Loads of people from my school are all suddenly coming onto Twitter, and I'm really worried that they're going to find my account, because Twitter is the one place I can escape from all the idiots at my school who judge me and don't understand me. I...

Hi, I am new to twitter. Can people you are following such as celebrities see your tweets (what you write about what you're doing) on twitter? or is it just people that are following you that can see your tweets? thanks

I'm just wondering, I don't have a twitter account but when I view someones twitter when it's not private can they get my IP address somehow?

say my friend clicks on my twitter link... can they by any chance go into my profile and see your email address? or is it hidden/no one can see it no matter what...even if i add them? i just don't want anyone getting my emails, and oddly enough...emailing...