The document discusses sustainable open source business models. It outlines four models: 1) single-vendor open source firms that derive revenue directly from open source software, 2) open source distributors that provide commercial support for open source, 3) developer foundations that manage open source development to lower costs for members, and 4) user foundations that finance open source development to reduce costs. The document argues that open source simplifies consortia by allowing collaboration between vendors, users, developers and other groups.