>>>>> "ML" == Mitchell Leben <email@example.com> writes:
ML> Let's say that all of the addresses are in different domains. Is there
ML> any efficiency to which addresses are grouped together?
ML> How does BM decide *which* 20 messages to group together, if they are
ML> all from different domains?
It just splits the sorted list into chunks. So domains will group together
if they sort near each other.
ML> Even if all addresses are on separate domains, there is still a benefit
ML> from multiple messages in the queue instead of one massive one.
Yes, because you are now delivering N chunks in parallel.
ML> This concept I understand, but I was wondering if BM does anything else
ML> besides check for the same domain.
Outside of sorting? Nope. Because of the way Sendmail works, you'll be
immune from hackers using EXPN to obtain your member list, though.