Under the GPL (version 2) you do not have to release source if your changes are hosted on a website. This is not currently considered distribution. GPL 3 looks set to change this.
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-With the GPL you can also remove all of the GPL code from your program and do whatever you want with your own code. (ex. you could write a program using GPLed libs, open source it, use your own source code from the app to write a different program, and keep that one closed source)
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This is true. You still own copyright on any changes you make. But if you release those changes under the GPL you can't revoke that code. You can do what you like with code that is yours.
For example: MySQL actually distributes under a dual-license. GPL for non-commercial use and a commercial license for everyone else. As MySQL (the company) owns the copyright they can set the terms of the code distribution.