As you are likely well aware, the Ext javascript library changed it’s license to the GPL. Instead of being reasonable people and choosing the LGPL, they want to enforce the spread of open source throughout the cloud. Sounds like a great idea, except that open source doesn’t always work. I’m a strong advocate of open source, but enforcing everyone that uses your software to suddenly be required to release their software under the GPL is a bad idea. Its the opposite of the spirit of the GPL, because it forces you to release the source of your software. You can’t do exactly what you want with it anymore.
The GPL was created to protect an author’s ideas about how their software should be used. Comparing it to other licenses such as the MIT license, the GPL is incredibly restrictive. It makes sure that source code released as open source stays open source. If something is added to it (like including it into a website’s programming), then everything that touches it must be GPL’d too. It can be quite a nasty virus. However, the LGPL tries to grant a little more freedom to the user of the software. It allows them to use the software how they want without having to release whatever uses it under the LGPL.
Releasing the Ext library under both the GPL and a commercial license effectively forces all users to either pony up some cash to use it, or they have to lose a bunch of cash by releasing their secrets under the GPL. If it used the LGPL license, they wouldn’t have to.
Then again, maybe I’m full of crap and nobody really understands how these licenses apply to a distributed language such as Javascript. Its only my two cents.