Colin Jackson as a transcript of his National Radio appearance last week. In it he explains the workings of the GNU Public Licence - GPL.
It is very good, and worth quoting if you need to counter uncertainty in your organisation about using software licenced under the GPL.
The Wildebest in my headline is supposed to be a witty reference to BSD style licences. My very finger in the air comparison of the two goes something like this:
1. They are both about freedom.
2. The GPL is about propagating the freedom of the software. Colin also describes it as an issue of "fairness" to the authors.
3. BSD is more about the freedom people have to do just what the heck they like with the software, including enslaving it.
4. Both philosophies are worthy but have different results.
To me, the propagating nature of the GPL explains some of the reasons for the success of projects using that licence. Certainly, if I were advising someone pumping money into an open source project I would advise them to look for a GPL licence.
I think a solid return on investment is far more likely to take place. That is, seeing the benefit of other people themselves taking up the mantle that the original investor has carried.
This has certainly been New Zealand's experience with Moodle, a GPL licenced online learning management system. A few years ago Moodle was a nice platform, had a good development community and a few hundred sites. A New Zealand TEC fund was used to add a number of features, not least amongst these were some very solid enterprise and performance capabilities.
Moodle is now used in over 13,000 sites and must be the world's most popular LMS. Investment from institutions such as the UK's Open University has now well exceeded NZ's initial investment. Yet because of the GPL New Zealand still gets to benefit from other peoples' significant work.
Contrast this with Apple's sexy desktop, which overlays a BSD version of Unix. Some code has been returned to the community but the nice stuff has remained secret, enslaved by Apple, if you will.
So, if you are a Government agency, or private funder, go GPL. If you are not worried about ever seeing contributions to your project, pick a BSD licence. Whatever you do, be aware of the differences.