@ryangorley the dual licensing of QT was pretty important back in the day too.
Joomla from Mambo.
Also, how Sun bought Star Office and open sourced it in the first place.
#ownCloud was under the gpl, and the main contributors formed a company to offer support, but then people in the company ended up choosing to make some extra parts of ownCloud closed source (like the iOS client).
Eventually, most of the original cow contributors forked the code, called it #NextCloud and then proceeded to work on alternatives to ownCloud's proprietary parts, making it all open source. That's about when it really took off.
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