All visitors to the chatter can read and search messages. In order to maintain some control over the chatter we require visitors to register before posting messages. When registering we ask for your real email address. Don't worry, we will not share or distribute this information with anyone else.
When returning to the chatter you can read and search messages without logging in. However you must "log in" before you can post a message. If you have cookies enabled in your web browser the chatter will remember your "log in" name. This eliminates "logging in" everytime you come to the chatter.