There is no way of knowing if someone visits your Twitter.
If the account is not protected then you can view it without anyone knowing.
If someone posts a link to a picture you can view it without them knowing. All they will know is how many people have viewed it (assuming they use a website that has a view count such as TwitPic) but they don't know which individual users.
If your Twitter account is not "protected" then anyone can view your profile.
The band CashCash does have a facebook fanpage for their group. On the page you have options to view their posts, pictures, twitter feed, and a link to download their music.
No. Everyone that is following you will be in your "Followers" list. However, if you do not have a protected account then anyone can view your tweets without you knowing. When you have a protected account you must approve who can follow you.
if one friend has a web cam and the other one doesn't
You can look at anyone's Twitter account without having an account. Simply type the URL in the address bar of your browser. However, if their account is protected/private then you won't be able to view it.
not often
Yes once a member you can view anybody's.
You can get a Twitter Universe account to chat about wrestling free but the events to watch are pay per view.
You can view their tweets by going to their profile. (the web address) However, if their account is private then you won't be able to see them.
There are various ones, you can view them from the website.