The text discusses the evolution of open source into what is referred to as its fourth stage, characterized by a renewed emphasis on collaboration, community, and commercial interests. This stage is exemplified by the membase.org project, led by NorthScale, which addresses the need for a simple, fast, and elastic NoSQL database, with contributions from both vendors and customers like Zynga and NHN. Unlike previous stages where cost was the primary driver for open source adoption, this new phase focuses on solving specific pain points with innovative solutions and fostering a collaborative environment. This shift marks open source as a crucial driver of innovation, particularly in infrastructure software, where open source components are increasingly expected. Open source 4.0 encourages participation from both corporate sponsors and individual contributors to further develop and strengthen the community.