GPLangelo
"I get tired of seeing people claim the GPL says you can't make money off covered software, or not sell covered software. The GPL says nothing of the sort. The GPL says you can't *prevent others* from sharing the software, its source code, or modifications to it, and that all modifications to it must also be under the GPL."
"RedHat makes money selling GPL'd software. Cygnus was making money selling GPL'd software before they were bought by RedHat. ArsDigita was making money selling GPL'd software before they brought in those outside VCs."
[Chris Hanson]
Yah sure you can make money off of GPL'd software, just not enough to stay in business. Just ask Eazel and Mandrake. :-)
GPL makes sure that you can't profit off of your intellectual property...why? Because it argues that it isn't YOUR intellectual property, it is everyone's [1][2]. You cannot make money off of "selling" the covered software:
"So unless you're going to draw distinctions carefully, the way this article does, we suggest it is better to avoid using the term ``selling software'' and choose some other wording instead. For example, you could say ``distributing free software for a fee''--that is unambiguous." [3]
You must make money off of something other than the software (support subscriptions, documentation, physical media, shipping and handling, "distribution," etc.). In fact, GPL specifically allows for what most companies would consider software piracy:
"if someone pays your fee and gets a copy, the GPL gives them the freedom to release it to the public, with or without a fee. For example, someone could pay your fee, and then put her copy on a web site for the general public." [4]
Yes, this means that according to the GPL, if someone obtains a copy of your software's source code, they can recompile it and sell it for whatever price they want. Just imagine if all software was like this. A lot of people would be out of jobs because sites like WAREZ.COM wouldn't be illegal any more, they would be encouraged. No one would have to think twice before downloading your software with Kazaa, because it would be perfectly legal. As the availability of high speed connections increases, linux installs start to work, and products become easy enough for people with a life to figure out, this is going to quickly become a major problem for the open source vendors that are still around.
Of course, if you are a one of the 14 year olds working flipping burgers by day and fixing up the kernel by night, this doesn't bother you, because programming isn't about making money, it is about having fun. But, if you are like most "professional" developers, as fun as you might have at work $5 bucks and hour from Micky D's doesn't cut it when you have a family to feed.
References
[1] GNU: Why Software Should Be Free: The Argument Against Having Owners
http://www.gnu.org/philosophy/shouldbefree.html
[2] GNU: Why Software Should Not Have Owners
http://www.gnu.org/philosophy/why-free.html
[3] GNU: Selling Free Software
http://www.gnu.org/philosophy/selling.html
[4] GNU: GPL Frequently Asked Questions
http://www.gnu.org/licenses/gpl-faq.html#DoesTheGPLAllowMoney