Coruscation

Path, which limits friend groups to 50, is among a new crop of Web services that allow people to connect with a handful of friends in a private group. Users get the benefits of sharing without the strangeness that can result when social worlds collide on Facebook. Other start-ups in this anti-oversharing crowd include GroupMe, Frenzy, Rally Up, Shizzlr, Huddl and Bubbla.

Even Facebook recognizes that people don't want to share everything with every "friend." It has privacy settings that control who can see what, but many people find these challenging to set up. So last fall, Facebook introduced Groups, for sharing with subsets of Facebook friends. And in March, it acquired Beluga, a start-up that allows sharing photos and messages with small groups privately.

Last month, Facebook said its users had created 50 million groups with a median of just eight members. It also introduced the Send button, which Web sites can use to let people share things with Facebook groups.

"We realized there wasn't a way to share with these groups of people that were already established in your real life -- family, book club members, a sports team," said Peter Deng, director of product for Facebook Groups. "It's one of the fastest-growing products within Facebook. Usage has been pretty phenomenal."