Sharing photos is one of those Silicon Valley evergreens. It's what drove Flickr, Webshots and other early dot-coms. In recent weeks, photo-sharing crossed over into the apps business, with startups Instagram and Picplz garnering big followings after splashy launches. But perhaps the most anticipated photo-sharing app to date has been Path, a company founded by former Facebook senior platform manager Dave Morin.

Path is different from almost any other photo-sharing tool to date, not because of what it can do, but because of what it won't allow you to do -- namely, share photos with more than 50 people. The idea is that Path allows users to be themselves, share photos and comments freely, and never worry about that awful "gotcha moment" when a boss sees unseemly images of a raunchy party. The core idea, really, is to focus on real connections: the 50 closest friends and family members you have.

This would seem to run counter to the whole purpose of social networks, which is to allow users to keep in touch with and keep tabs on larger groups of people. Morin and his team believe that's merely an illusion. They say 150 is the greatest number of personal relationships a human being can comfortably maintain, and 50 is a sweet spot for people who are truly close and in regular contact. They base this assumption on research from evolutionary anthropologist Robin Dunbar (who established "Dunbar's Number" of 150 maximum effective acquaintances), among other scientists.

But Path goes even further than limiting the network size. Members of your network won't be able to comment on or "like" pictures you post. This will seem counterintutive to social media gurus, who claim engagement is the best thing since sliced bread. To like-happy Facebook users, stripping out this part of the photo-sharing experience may seem crippling. But it alludes to the possibility that Path might be doing something that Facebook could easily do itself in the near future -- namely, give users even more options for turning on or off sharing features as they please. (Facebook is certainly heading that way.)

Path launched as a mobile app (initially iPhone only) on Nov. 14, and it's a heavily anticipated startup backed by big-ticket venture capitalists. Morin is viewed as one of the more promising young tech gurus in the Valley, with an extremely good grasp of social media dynamics. Without a doubt, he's chosen a road less traveled in his initial feature set for Path. Watching his progress will be an interesting exercise.