Called The Coop, the project aims to build a browser add-on that will let people share and receive links or other Web-delivered content, such as photos.
Project planners envision a row or column of boxes that contain their friends' photos, which could be pulled from an online photo-sharing service like Flickr.
The person will know that something has been sent when a friend's avatar or picture glows. Or a person can click on a friend's avatar to get his latest bookmarked Web pages, photos, blogs or movies.
"Perhaps the most common social interaction on the Web today is sending someone a link," the project's Web site notes. "The goal of The Coop is to ease this interaction and merge it with similar tools provided by a large number of popular Web services."
Like a chicken coop, each friend's avatar will have its own box, where it "lives."
Information could be transported between people's browsers either using RSS feeds or setting up an instant-messaging server, according to the project's Web site.
The project is now at a "proof of concept" phase, but Mozilla has already sketched out anticipated features such as letting someone drag a link onto a friend's image to share it.
Another browser designed around online social services like Yahoo's Delicious and Facebook isstill in the beta-testing phase.