Unless otherwise stated, any open source Elegant Chaos software is distributed under the terms of the GNU General Public License.
Choosing exactly which license to use has been tricky, and I may revisit this decision at a later date (but any change will not affect the software that I am distributing now).
Politically I agree with the aims of the GPL, and I understand why it imposes the restrictions that it does.
I did have a couple of concerns with it:
First, as someone who has worked on lots of commercial software, I do understand that the GPL can be a monumental pain in the arse. It is often totally unrealistic to expect a product to be open sourced when selling it is the raison d'être of the whole company, and a programmer is often left in no doubt how their boss would react to such a suggestion.
In these cases the GPL license may have some long-term evolutionary effect, killing off such commercial narrowmindedness, but in the short term the programmer quite likes their job, so has to forgoe a nice clean public implementation and attempt to re-invent the wheel. This is a shame as it works against standardisation and encapsulation of common code, both of which are desirable processes that all programmers benefit from.
For now, I can live with that effect of the GPL on my software, because the things I'm releasing are so small that the standardisation argument is irrelevant.
My second concern was that I didn't prejudice any future need that I might have to commercially exploit my own work!
This is perhaps selfish, but it's also a pragmatic concern, because I don't know what the future will bring. Until I reach the enviable position of being financially secure for the rest of my life (looking extremely unlikely from where I sit right now), there is always the possibility that I'll need to use some of my code to pay my rent, so it seems unwise to preclude that!
I think that this concern is answered positively by one of the GPL frequently asked questions.