coffeedate
a vaporware program in which you broadcast your availability for coffee during certain hours. If someone from your friends list also broadcasts their availability, both people are notified. If GPS is enabled, relative distance can be an additional criteria.
Privacy is inherent as information is exchanged if and only if there is mutual availability. GPS zones can be set in which you do (or don’t) broadcast your location. The more criteria that is added, the less likely that it will be met, or conversely the more friends you will need.
TODO:
1. Add GPS broadcast/blackout zones to http://code.google.com/p/osmdroid/
2. Add status flags to your marker
