These services pop up from time to time. All they share a fatal flaw: accepting money for email delivery turns email from a communication medium into a service.

These services pop up from time to time. All they share a fatal flaw: accepting money for email delivery turns email from a communication medium into a service. And a service carries a different set of obligations - someone paying to send an email to me expects that they are buying my time spent on reading their email and replying promptly. I am never going to sell my time like that.