What is the purpose of the quote from Zimmermann? It explains how much faster e-mail travels than ordinary mail. It shows how easily digital mail can be monitored by outsiders. It states exactly how many people use e-mail instead of regular mail. It proves that e-mail is better for the health of democracy than regular mail.

I had to look for the quote which was referred to above from Zimmermann and the answer would be the first option. The main purpose of this quote is to let the readers know how much faster e-mail can travel compared to an ordinary mail. Ordinary mails would take days to receive whereas e-mails would only take minutes because it is digital.