I tried Outlook first (copied about 250 email addresses into the CC box). Boom. What a mess. I confess I may have accidentally sent the same email to everyone on that list up to 3 times, as I tried to work through the pile of returned mail I got from various mail servers who couldn’t deal with such a long list of receipients in a single message. (Oh, and by the way, who the HELL thought of the ridiculously uninformative error messages baked into just about every mail server? Some of them aren’t even proper sentences and give me no clue as to what action [if any] the server took after the error. Were the messages not forwarded at all? Did it go to only some of the recipients? If so, which ones? Sheesh. Time for an upgrade guys!) That’s when my eyes were opened to the fact that you actually need specialized software to deal with email campaigns of more than about 25 recipients.

I've used a qmail server to send messages to 14 000 or so people, and it works -- but watching the logs is breathtaking.

Great Email Campaign Product: Campaign Monitor