Another aspect is that many popular e-mail providers and applications are problematic. For example, I have experienced Microsoft’s e-mail services reformatting e-mails sent via Microsoft. This breaks code sent by them in e-mail, even in text attachments.
Also, many e-mail providers are not using monospace fonts or otherwise disrupt how others expect their e-mail look when received. A mailing list web interface may help these users. Regards, Florian