One of the crucial point I am facing is that of being able to monitor the SMS activity of the participant of the field trial of STAMPS. This will provide useful information to compare the spatialized messaging with canonical strategies of communication. There are a couple of technical limitations which prevent a direct monitoring on the outgoing box so I have been thinking on possible workarounds.
1st solution: monitor the inbox for incoming messages from one of the group participant. This will require to know the numbers of all the participants which is possible. One of the limitation is that it will also parse other messages with possible infringement of the privacy.
2nd solution: ask the user to use a second phone knowing that this second device, the SMS exchanges will be monitored. A bit more fair but not practical to hang around with two phones in the pocket.
3rd solution: implement an internal private and direct one-to-one communication with other participants. This will be mostly transparent to the user but it will face the risk of not being used because people are accustomed to current SMS mechanisms.