"During 2008 it became clear that the open core approach - in which the core software is open source while an enterprise version is also available with proprietary extensions - has many benefits for vendors of open source software, including providing up-front revenue and in balancing the requirements of community and enterprise users.
"Proprietary vendors tapping into the benefits of open source development tend to generate revenue from other products or embed open source within larger commercial products, rather than building proprietary extensions on top of open source (think of IBM's use of Apache within WebSphere)."
