  We introduce a novel wireless device-to-device (D2D) collaboration
architecture that exploits distributed storage of popular content to enable
frequency reuse. We identify a fundamental conflict between collaboration
distance and interference and show how to optimize the transmission power to
maximize frequency reuse. Our analysis depends on the user content request
statistics which are modeled by a Zipf distribution. Our main result is a
closed form expression of the optimal collaboration distance as a function of
the content reuse distribution parameters. We show that if the Zipf exponent of
the content reuse distribution is greater than 1, it is possible to have a
number of D2D interference-free collaboration pairs that scales linearly in the
number of nodes. If the Zipf exponent is smaller than 1, we identify the best
possible scaling in the number of D2D collaborating links. Surprisingly, a very
simple distributed caching policy achieves the optimal scaling behavior and
therefore there is no need to centrally coordinate what each node is caching.
