Path is the best thing that happened to social network in the past few years.
It combines the best of Instagram-Camera+, Facebook, Twitter and Foursquare in an slick and elegant app.
I have been using it for a little more than a month now and it’s simply wonderful. The UI/UX is a delight. The social networking experience is great (limited to 50 friends).
Most importantly the network lives at a very pleasant pace: less noise than on Facebook and less intense than Twitter, a human pace.
It has become, by far, one of my most used app along with Twitter on iPhone.