How can I control who can see my entries?

How can I control who can comment on my entries?

How do I set up groups?

How do I make an entry that is private to myself or my friends?

What do the padlock icons mean?

How do I control who can write entries on my blog?

What are contributors?

How do I add a contributor?

How do I remove a contributor?

Will I get more junk email if I have a blog?