[PeterWhittaker]

I believe you're right, that was my conclusion as well. I'm not sure that that will accomplish what they hoped.

To continue my original example, I could, in theory, take this code, ensure that it works with arbitrary independent pseudo-services, create my own such services, under a proprietary licence, and distribute the whole as an aggregate, which is permitted by the GPL.

The author likely seeks to provide commercial licensing for those interested in integrating their pseudo-services as libraries, which would require either that they be GPLd or that the original code be licensed in some other way.

I hope the author achieves the success they hope for without the licensing and legal hell they may have set themselves up for. It can be a great disappointment to have one's work turned into someone else's success by a someone or someones with more legal and licence cunning than one's self.

(Note: that ain't me, I've just seen that exact scenario playout more than a fair few times....)

[tptacek]

Yes, people can do that. It's inconvenient and risky, so serious customer prospects will pay to avoid it. This is one of the more common open source commercialization strategies; one of the earlier examples is Sleepycat.