How ClickMail works
The basic purpose of ClickMail Central Directory is to provide a master address book that a group of people can use to look up email addresses.
When a user wants to send someone email, he/she opens an email program, types in part of a name, and clicks Find. The email program asks ClickMail for the email addresses of everyone who's name contains "Fred" (what the user typed). ClickMail sends back a list of people who match, including name, email, and possibly other attributes such as phone, pager, address, etc. The user selects a name and clicks a button to create an addressed message. If you don't want to access a server every time you need an email address, the email program stores captured addresses in a local address book.
ClickMail is compatible with many email programs because it uses the Internet protocol, LDAP (Lightweight Directory Access Protocol). It works with LDAP v2 clients and LDAP v3 clients (not all features of v3 are implemented).
Per LDAP, ClickMail keeps a directory containing entries for the people listed. Each entry contains attributes that describe the person, such as common name, email address, telephone, etc. LDAP clients can search using one or more attributes ("Give me all Joneses in the Cleveland office that have fax numbers"). Or they can just download all the entries into their local address books (depending on permissions and maximums set by the administrator).