On Wednesday, Mr. Stone took the wraps off Jelly, a platform that bears a passing resemblance to Quora – users ask questions, and members of their extended network answer them. But in the case of Jelly, questions can be posed and answered with photographs. (The name of the company, incidentally, refers not to the spreadable condiment, but to the protean sea creature, which is also Jelly's logo.)
An example: You're on vacation in Boston. You pass a large granite obelisk. You're not sure what the object is. So you use your smart phone to snap and upload a photo to the Jelly app. Soon, a friend responds: That's the Bunker Hill monument you're looking at.
"Jelly is designed to search the group mind of your social networks – and what goes around, comes around," reads a post on the official Jelly blog. "You may find yourself answering questions as well as asking. You can help friends, or friends-of-friends with their questions and grow your collection of thank you cards. It feels good to help."
Jelly is currently available on the iTunes and Google Play stores; the app is free to download.
Stone, who left Twitter in 2011, has been working on Jelly for years. Among his investors, according to the Jelly site, are Jack Dorsey, Bono, Al Gore, and TV director Greg Yaitanes.
In an interview with Fortune, Mr. Yaitanes called Jelly "one of the investments that I am most excited about... Jelly helps you think of what your friends might know when you have a question," he continued. "At a time when there is only four degrees of separation between people, the idea that we can be connected by our knowledge is powerful. Everyone has a story – Jelly taps into that."