They began working together shortly after they met, and in March 1995, with MIT professor Pattie Maes, engineer Max Metral, Upendra Shardanand, and Yezdi Lashkari, Grouf and Waxman founded Firefly.
Originally known as Agents, Inc., Firefly invented collaborative filtering personalization technology which could predict a user's tastes based on previously gathered preferences.
As the CEO and president of Firefly, Entertainment Weekly wrote that Grouf gave "cold artificial intelligence a warm glow.
"[9][10] Firefly, which collected large amounts of personal data, implemented tools and systems for users to manage and note privacy preferences.
Key contributors to OPS (Open Profiling Standard), the company developed the underlying data management technology which was later known as the P3P (Platform for Privacy Preferences).
Its business model included collective buying, which allowed the company to generate additional revenue from advertising, partnerships, and premium products.
[17][18] In February 2000 the company announced that they would provide PCs and Internet access to all of the employees of Ford Motor Co. and Delta Air Lines, and in October it was announced that it would open European subsidiaries to enable overseas corporations and governments to offer their employees low-cost home computers and Internet access and later developed partnerships with Vivendi Universal, The New York Times, Blue Cross Blue Shield, and the National Trades Union of Singapore.
Based on their experience with the Kerry campaign, Grouf and Waxman founded Spot Runner, a service which allowed business to customize a pre-produced television ads, set a budget, and target specific markets.
Fast Company wrote: "The pair wedded the democratic spirit that underpinned PeoplePC to a variation on the recommendation engine that powered Firefly.
"[8][23] Grouf led the development of Spot Runner’s Malibu Media Platform, a marketplace for buying and selling national and regional ad time.
Through Clementine, Grouf has provided resources, capital and strategic guidance for independent entrepreneurs and early-stage companies in both the consumer and business-to-business sector.
He serves on the board of directors for The Hammer Museum, LAXART, Trajal Harrell Dance Company, and Larchmont Charter Schools.