...and how do you absolutely prevent "commercial" e-mail on your mail server?
anything that links amateur radio to the internet IS commercial.
They have an email white list.
APRS is also connected to the internet. Is that illegal too?
I tried to find where else it may be illegal, looking at all one-way comms, message forwarding, etc., but cannot really find an absolute rule.
The rest of the arguments I've read are based on operating practice, not the concept.
It's difficult to accept ...97.113 (2) & (5) since, (2) where is anyone getting paid for the transmission, and (5) is the comm regular and could it really be reasonably furnished by a commercial service? This is even more problematic since just about any basic amateur radio comm could be reasonably provided by other radio services.
The one that gets it is 97.115 (c) with all its intent...
I consider sending a digital email/text message as a one-way transmission, which does not seem to be authorized (or where does it fit?):
Permitted One-Way comms:
(41) Space telemetry. A one-way transmission from a space station of measurements made from the measuring instruments in a spacecraft, including those relating to the functioning of the spacecraft.
(43) Telecommand. A one-way transmission to initiate, modify, or terminate functions of a device at a distance.
(45) Telemetry. A one-way transmission of measurements at a distance from the measuring instrument.
(b) In addition to one-way transmissions specifically authorized elsewhere in this Part, an amateur station may transmit the following types of one-way communications:
(1) Brief transmissions necessary to make adjustments to the station;
(2) Brief transmissions necessary to establishing two-way communications with other stations;
(3) Telecommand;
(4) Transmissions necessary to providing emergency communications;
(5) Transmissions necessary to assisting persons learning, or improving proficiency in, the international Morse code;
(6) Transmissions necessary to disseminate information bulletins;
(7) Transmissions of telemetry.
(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules; nor shall an amateur station engage in any activity related to program production or news gathering for broadcasting purposes, except that communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.
(e) An auxiliary station may transmit one-way communications.
(g) A beacon may transmit one-way communications.
(e) A space station may transmit one-way communications.
(d) A telecommand station may transmit one-way communications.