Well, there are many reasons you could need an urgent email for something that wouldn't be satisfied over the phone. Sending a contract or a statement of work, for example. Sure it could be faxed, if both parties have fax. It could be put on Dropbox, if both parties have Dropbox, etc.
If it's not just a communication but rather an exchange of data, a phone call won't suffice. The author even mentioned that he had called the person, who resent the email 4 times. Obviously a phone call isn't what needed to happen. There's just a lack of good file transfer solutions on the Internet.
Should be "order of magnitude more".
Getting really tired of tech writers using "orders of magnitude" hyperbole when its not really the case.
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Also don't like him complaining on not receiving an "urgent" email in time. Urgent communications require phone calls.