Remember to verify the address you are sending to.

To send an email to a @smumn.edu address is very easy with GoogleApps.  Maybe too easy...

We've received reports that senders are not selecting the correct email address when attempting to send an email to a recipient with a common type of name. Be aware that we may have staff or faculty with the same first/last name as students or student's with the same first/last name.  If the incorrect email address is first in the drop down list you may choose it instead of looking at the email address to verify it's the member of the community you intend to email.

For Example:  While composing a message to Jennifer Johnson I have two email address options, one  with 08 at the end of the email address and one with 09 at the end of the email address.  I need to select the correct address so that my message gets to the appropriate person.

This is one example, I'm sure many more exist.  Please watch who you send messages to so that you can be sure that communication is timely and effective.