[every_other]

This is cool! I had been thinking about creating something similar but I couldn't solve this problem:

Given a radius of 5 miles and three users in a geographic straight line, each 4 miles from each other. User 1 and user 2 are in the same radius, user 2 and three are in the same radius but user 1 and 3 are not in the same radius. Therefor user 1 and 3 will only see "half" the conversation (which would obviously be confusing). Do you solve for this problem? if so, how?

[unoti]

An idea of how to solve that problem: connect a user to the closest person if there is nobody in their radius. Use Disjoint Sets to sort of glom people together like pieces of cereal in milk. Everybody in the same glob can hear each other.

[michaelt]

You could divide the country into segments, and a person gets to talk to everyone in their segment.

Obviously, you'd want smaller segments in areas with a high user density, and larger segments in areas with low user density.

You could generate segments with something like EM clustering. You probably wouldn't want continuous segment recalculation, or two people could be split mid-conversation when neither of them had moved.

[nemasu]

Nope, they would need to increase radius.