Facebook made oversharing with a small army of friends a mainstream activity.
Now, one of its early architects is swinging in the other direction.
Dave Morin, who helped build Facebook Connect and the Facebook Platform, left the company this year to start his own venture, called Path. He says it is not another social network he has created, but a personal network, and on Monday, it will open to the public with an iPhone app for sharing cellphone photos with a limited circle of friends.
Each user cannot have more than 50 friends.
Path is a reaction to Facebook, where people must both agree to be friends, but can have thousands of them, andTwitter, where anyone can choose to receive a user’s posts.
“If you look at how these networks are grown, they start out really high-quality,” said Mr. Morin, “and as more and more people join, it becomes hard to find people you care about. With Path, you have to be friends with them in the real world in order for them to pop up on your screen.”
Path, which is starting with the iPhone app and a Web site and plans to build apps for Android and BlackBerry, has kept its plans shrouded in secrecy. It now joins a growing list of similar apps, like Instagram and PicPlz. The apps are part of several big trends. As cellphone cameras have improved, people are taking more photos than ever before. Tech entrepreneurs and investors are betting that these photographers also want to share their handiwork, especially in real-time and linked to their location.
Path, along with the other apps, wants to build a broader mobile network, not just photo-sharing apps. It envisions people using a new mobile social network, in addition to Facebook, to share photos, videos and other things with a close-knit group. However, the rival apps differ from Path by offering software filters, which change the way photos look. They also follow Twitter’s model, so any user can see anyone else’s pictures.
Path is counting on people wanting a more controlled network of trusted friends. Mr. Morin chose the number 50 based on the research of Robin Dunbar, an anthropologist who tried to pinpoint the maximum number of people with whom others could have stable relationships. The Dunbar number, generally thought to be around 150, is a popular topic of discussion in Silicon Valley among people building tools to communicate virtually with thousands of people.