Hi,
The only thing coming close to it in scalability is Critical Path.
Does the windows version of Critical Path still exist? ;-)
After all it's a good/stable product. (Well: i dislike the CP-smtpd .. it works unless you try to do anything funky .. but replacing it with postfix/qmail isn't a problem)
Both Yahoo Mail and Google Mail (Gmail) started off the qmail-ldap code base.
gmail used the qmail codebase? Do you have any reports/documentation about this?
AFAIK they wrote the smtpd from scratch. Porting qmail to googles non-posix GoogleFileSystem doesn't sound like fun and in the early days it had a few bad quirks.. (like: sending long strings crashed googles smtpd)
Regards, Adrian