I just downloaded PowerMail 5.1b3 for evaluation. The first thing I notice is that PowerMail does not respect Group Distribution Lists from Apple's Address Book. Is this a known issue which is being worked on?
Example: I have a group in Apple's Address Book with 14 people assigned to it. (Each of those 14 people has multiple e-mail addresses.) In Apple's Address Book, I use the Edit Distribution List command to select which address should be used for each individual when using this group. After importing the address book into PowerMail, and when I select the group as the recipient of the mail, many of the wrong e-mail addresses get used. Dave Burbank