To make sure you write emails following the guidelines, read the Netiquette Guidelines - RFC 1855.
Or play this game of goose (in French): Quelques règles pour les emails
This can be done with several email clients (MUA = mail user agent).
I used the following at some point:
LDAP address book
I have installed LDAP on my server and tried a few email clients and address books:
- MailApp + Address Book
The biggest problem is that the mail clients and address books don't use the same schemas.
They only items they have in common (that I am interested in) are:
- first name
- last name
- one email address
- phone at work
- mobile phone