When posting a notice to give something away, many people will not want to publicly post their email address or phone number. You can use the Private Messaging feature of this site to communicate privately with each other about an item. Simply use the PM button on a notice to send a private message. When you log into the site you can view your private messages by using the menu at the top of the page.
The Private Messaging feature is a simple email system and all of the messages stay on this system. By editing your Profile using the Profile link at the top of the page you can instruct the system to notify you when you receive a new private message. You will then receive an email telling you to check your private messages.