Great question — answering as the UphillTech team:
For me there is a technical limitation/risk here -> the mobile device, and its connectivity. 1) What are your requirements? Do you need to support various mobile devices or will you focus on only one platform ? 2) More importantly, you have to understand that GPRS data connections differ from a PC connected to the Internet. There are various connection restrictions imposed by different mobile operators. If I was to design such a system in order to minimise those risks I would go with a web server running on port 80 which the mobile devices would upload their Long/Lat through POST (or even GET to simplify things). EDIT: Regarding scalability, it would be very easy to scale things up in the...
Full answer by Iraklis: https://stackoverflow.stackexchange.com/a/2528878 (CC BY-SA 4.0).
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