What are some examples of open source software that has turned into closed source software? [on hold]
As the title says... can anyone think of any software that has made the transition from open source to closed source / proprietary?
These could include software owned by the same company who decided to take a once open source offering and turn it into closed source... but I'm really looking for some examples of companies who developed a commercial closed source product off of an existing open source one (obviously with a permissive license).
© Programmers or respective owner