Redis is a popular open source database. Its proprietor, Redis Labs, recently announced that some add-on modules will not be open source any longer. The resulting outcry led to a defense and explanation of this decision that is telling. I have two comments and a lesson about product management of commercial open source.
The two comments are about messaging, both ways: What Redis Labs is telling the world and what the open source world is telling Redis Labs and the rest of the world.
Firstly, by restricting usage of these add-on modules, Redis Labs is admitting that someone else is successfully competing with them in their own game. The bogeyman is AWS (Amazon), in this case, as called out in the defense of the Redis Labs decision. Usually, the original proprietor of some open source software is in a prime position to profit from it, being the most trustworthy choice for customers and being able to charge a premium. AWS has to white-label the software (remove any of Redis Labs trademarks) and still is a serious threat. Admitting this is as embarrassing as it gets.
Secondly, rather than taking any future development of the add-on modules private, Redis Labs decided to fiddle with the license by adding a rider that makes it non-open-source but still permits many open-source-like behaviors. The intent may have been to stay as close to open source as possible, but this behavior has nevertheless annoyed many open source enthusiasts, leading to the aforementioned outcry. Thus, the open source world is telling Redis Labs that of the many sins you can commit as a commercial open source company, the worst is to go back on your legal (read: license) open source promise.
You may like reading this older article about how the single vendor commercial open source business model works. Also, there are other ways of curtailing your competitors, if you must: Read more about the kitchen cabinet of open source poisons.