As a partial answer to your question, I for one thought that Zed's final point made sense (and made me better understand the GPL):

Open source to open source, corporation to corporation.

Basically, you can do just about anything with MIT- or BSD-licensed software. But the GPL tries to make everything around it GPL too. If you build software that integrates with a GPL'd library, you have to release your software with a GPL (or similar) license.

So Zed's plan is to offer his software under a GPL license for free (open-source to open-source), and also sell it without the GPL license for pay (corp to corp).

Good place to go for GPL info: the GPL FAQ (http://www.gnu.org/licenses/gpl-faq.html)