The Physics of Friendship Rather neat! They’ve taken the theories of particle movement in Physics, and applied it to Social Networks.
Note: There are sponsored ads on the page, which are both irritating & not relevant.
After a collision, a particle moves in a different direction with an updated velocity, just as how an individuals chance of meeting a new person depends on their most recent acquaintances.
The full article is: System of Mobile Agents to Model Social Networks, Marta C. González, Pedro G. Lind, and Hans J. Herrmann Phys. Rev. Lett. 96, 088702 (2006) [Subscription needed]