Craigslist help: If I am replying to an ad that someone else posted do i need to give my email?

-I want to communicate with other people who use craigslist but am unsure how. when I reply to someone's add, do I need to include my email address in the email so that they can reply to my reply?

OR does craigslist have "my mail", "my messages", or "mail" section- will the person that I initially replied to (their add) reply to my message by sending a message to the "craigslist email"?