Don't forget, APRS is not about sending your GPS position. That is simply a part of the whole thing (although it seems to be the most popular). It's all about local tactical data distribution. The kind of data that is distributed is, of course, lat/lon coordinates of objects, text messages, and telemetry. The data can be generated automatically by microprocessor devices, or by an operator. When the data is sent, all receiving stations will see it and operators can act on it. Originally 'all receiving stations' meant 'those radios tuned to the local frequency', but now it could mean any station hooked up to the internet if desired.