Many people, even some lawyers, don't understand the GPL. :/ It elicits this kind of knee-jerk reaction in people.
I've been in discussions about problems with the GPL in several companies already. The real problem is not (as most people tend to think) the requirement to provide source code and the rights to modify and redistribute it. The problem is the patent claim landmine that is considered to be dangerous by many lawyers (see GPLv2 Section 7, LGPLv2 Section 11). I don't want to go into excessive detail here, but in brief: the danger is that you might have to immediately stop redistributing the software if you become aware of a patent that would restrict the rights provided by the GPL.
A library project which is under GPLv2 or GPLv3 gets immediately rejected in many (most?) commercial settings. Note that I'm not judging here — just stating a fact. We ourselves reject a lot of interesting options because of licenses and I know most other companies do so as well.
Now, LightTable is not a library project, but I can imagine how companies would like to bundle it, or bundle a modified version of it. The moment you "redistribute" it, the GPL applies, and if you build a business on this software, that business might have to suddenly fold some day because of patents.
Please don't respond along the lines of "you might get a patent lawsuit anyway". Yes, you might, but then it's a lawsuit, which you can defend against.
Please understand that the license change is a really big deal for some people.
While this also may be true, I'm quite familiar with the patent issue. And I am not even really criticizing Light Table for this decision, just expressing a tinge of sadness that yet another project has switched to a non-viral license.
> Please understand that the license change is a really big deal for some people.
Yup, I'm one of them.
The GPL sacrifices developer freedoms for end-user freedoms. I don't think it's any inherently more or less free. But then you get into discussions of what 'freedom' means...
I have written a ton of software licensed as each, and the tide is certainly turning toward the BSD. It just bums me out.
For the end-user it's irrelevant what license a product uses. They buy a polished, boxed product; they don't download source code, set up the code's build requirements and then compile it.
The only practical benefit of open source products for the end-user is that there may be forks of it which could have an impact on the price (although a product is more than just its source code, so they may not even be interchangeable). Or that someone could pick it up if the original developer abandons it. But these are theoretical long-term benefits, not immediate ones like those for developers or the code itself.
I'm not saying the GPL is bad. Just that people often misunderstand its motives. The GPL is about code in the same way PeTA is about animals. If the humans benefit directly from it, that's great, but the primary motivation is an ethical absolute: code should be free, locking it behind proprietary licenses is against its nature.
GPL and BSD/MIT-style licenses are not equivalent in this regard, because code under BSD/MIT-style licenses is not obligated to be either easily attainable or modifiable. You can ship binaries and not release source code.
You can profit from GPL code. MySQL is perhaps the best example but there are others.
Keeping the source open is a big deal, because communities and projects can die otherwise. More than a few game mods, for example, have died because the developers closed the source to mitigate cheating, and then stopped developing the game altogether. Under the GPL, this could never happen.
This separation between "developer" and "end-user" is common, but by no means absolute; there are many examples of non-professional developers adjusting their own tools such as scientists, business analysts, financial advisers, etc.
Besides, the GPL also grants the right to share the binaries with other people, which is definitively something that every end-user does.