I wrote earlier that for me personally, one of the biggest benefits of practicing martial arts has been the instant camaraderie and the long-lasting friendships built doing it. I find that photography is somewhat similar in that respect. Perhaps, people naturally tend to build social networks around their activities, particularly if there is a true interest or passion in those activities.
Granted, connections with other photographers is typically not as instantaneous as with fellow kendoka or motorcycle riders. When the two hobbies/pursuits intersect, however, the common field of mutual interests becomes so vast that interacting with other photographers sometimes is often the most interesting aspect of a particular photoshoot.