12 tips for better e-mail etiquette

1. Be informal, not sloppy.
2. Keep messages brief and to the point.
3. Use sentence case.
4. Use the blind copy and courtesy copy appropriately.
5. Don't use e-mail as an excuse to avoid personal contact.
6. Remember that e-mail isn't private.
7. Be sparing with group e-mail.
8. Use the subject field to indicate content and purpose.
9. Don't send chain letters, virus warnings, or junk mail.
10. Remember that your tone can't be heard in e-mail.
11. Use a signature that includes contact information.
12. Summarize long discussions.
    

Extracted from http://office.microsoft.com/en-us/FX012055341033.aspx