It's the predictable margin between cost to provide service and the value of convenience to the customers.
The marginal cost of sending a fax is, arguably, about one cent. (1.8c/min VOIP cost, 30 seconds to send, some electricity). Most faxes will be one page anyway, so the profit margin is a nice 10000%.
Finding a working fax machine if you don't have one sitting around all set up is a hassle on the order of 10 minutes to an hour, and likely to end up with a visit to a UPS/FedEx/Staples or the equivalent thereof, where they will charge you $1.50-$2 for the first page anyway.
Find a cheap old technology that people want to use infrequently and are therefore willing to pay a relatively large markup for convenience. Let's see... appointmentreminder already does voice calls for reminders, but how about automated, customized calls? Get a good speech synthesis app and let people send and schedule calls that read out whatever they want to type. That's probably worth a buck to people who only want to do it once, and then you can offer a subscription rate for frequent flyers.
The marginal cost of sending a fax is, arguably, about one cent. (1.8c/min VOIP cost, 30 seconds to send, some electricity). Most faxes will be one page anyway, so the profit margin is a nice 10000%.
Finding a working fax machine if you don't have one sitting around all set up is a hassle on the order of 10 minutes to an hour, and likely to end up with a visit to a UPS/FedEx/Staples or the equivalent thereof, where they will charge you $1.50-$2 for the first page anyway.
Find a cheap old technology that people want to use infrequently and are therefore willing to pay a relatively large markup for convenience. Let's see... appointmentreminder already does voice calls for reminders, but how about automated, customized calls? Get a good speech synthesis app and let people send and schedule calls that read out whatever they want to type. That's probably worth a buck to people who only want to do it once, and then you can offer a subscription rate for frequent flyers.