They announced their project on April 24. They reached their $10,000 goal in 12 days, and the money continues to come in: as of Tuesday afternoon, they had raised $23,676 from 739 backers. “Maybe 2 or 3 percent of the money is from people we know,” said Max Salzberg, 22.

Working with Mr. Salzberg and Mr. Grippi are Raphael Sofaer, 19, and Ilya Zhitomirskiy, 20 — “four talented young nerds,” Mr. Salzberg says — all of whom met at New York University’s Courant Institute. They have called their project Diaspora* and intend to distribute the software free, and to make the code openly available so that other programmers can build on it. As they describe it, the Diaspora* software will let users set up their own personal servers, called seeds, create their own hubs and fully control the information they share. Mr. Sofaer says that centralized networks like Facebook are not necessary. “In our real lives, we talk to each other,” he said. “We don’t need to hand our messages to a hub. What Facebook gives you as a user isn’t all that hard to do. All the little games, the little walls, the little chat, aren’t really rare things. The technology already exists.”

The terms of the bargain people make with social networks — you swap personal information for convenient access to their sites — have been shifting, with the companies that operate the networks collecting ever more information about their users. That information can be sold to marketers. Some younger people are becoming more cautious about what they post. “When you give up that data, you’re giving it up forever,” Mr. Salzberg said. “The value they give us is negligible in the scale of what they are doing, and what we are giving up is all of our privacy.”

The Diaspora* group was inspired to begin their project after hearing a talk by Eben Moglen, a law professor at Columbia University, who described the centralized social networks as “spying for free,” Mr. Salzberg said.

The four students met in a computer room at N.Y.U., and have spent nearly every waking minute there for months. They understand the appeal of social networks.