What they have effectively done is built up a community, taking full advantage of the open source model by accepting user contributions and patches and then turned around and kicked their own community up the backside. It is projects like Ext-JS that give open source a bad name. How can a company have faith in open source if the people behind it can’t even decide how to license the thing?
Project[s] that start using a commercially liberal license and then switch[ licenses] long into the life of a project is wrong. If you want to do the GPL/commercial thing then say so from the start. [There is] nothing wrong with this model, but for libraries and tools using a commercially liberal license is the best way to get community adoption and then to flip the license I find a little unsavory.
Anyone interested in forking it and maintaining the version that was not GPL?
In related news, ActiveMQ is opting to move away from Java Service Wrapper.
Update (5:45 PM Central): A little madness thinks ExtJS has discovered step 2 of the elusive Slashdot business model:
The model works because step 1 allows you to build a community around the more liberal LGPL license. In particular, as the LGPL is commercial-friendly, the community will include many people building commercial applications. Once the community is suckered in and committed, the license is changed, leaving them high and dry. Well, not quite: they can continue to use new versions of the library by buying a commercial license. Hence the profit!
Update (6:17 PM Central): More from Stephans Blog