Originally Posted by ErikD
Or is it more you have one email acount as the main one(BES), and can then just receive email from others but all gets sent through BES?
Almost. You can have one BES and up to 10 accounts integrated with BIS.
If your carrier is not using BIS 2.0 or better, your BIS account can mimic one email account (making it appear as if you're sending from that email account).
If your carrier is using BIS 2.0 or better you can appear to send from any of the BIS-integrated email accounts.