I used to think that spreading the Free Software philosophy through advertising, as companies usually do, would be more moderate and more acceptable to people (more infectious) than spreading the Free Software philosophy in a coercive, copyleft-based way, such as the GPL.

So I came up with the idea that instead of copyleft, there should be a permissive license like the Apache or MIT licenses, with only a new "Free Software Philosophy Advertising Clause" added. This clause would say, for example, "In a prominent place in the software's user interface, you must include a short propagandistic phrase that promotes the basic philosophy of Free Software and a URL link to a longer educational statement" and "This Free Software philosophy advertising clause also applies to derivative works."

Regardless of the validity of this idea*, I thought that someone had already thought of this idea. Is there a "Free Software Philosophical Advertising" license that already implements this idea?

* This idea has an evil "ends justify the means" quality from a free software perspective, and in practice it is doubtful that such a clause would work well in the examples given. At the very least, it will no longer be GPL-compatible and will not be OSI-approved.

Added on 2/13/2023: Or is there a movement somewhere to create a standard and compatible license based on this idea, to prevent the proliferation of advertising statements as it did with the 4-clause BSD?

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    What about software with no user interface? Would it not be equivalent to permissive license? (Ie, it could be worked around by splitting off the user interface into its own application that spoke to the main application via a REST API). Feb 13, 2023 at 15:39
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    @user1937198 actually what is relevant is the arm's length development model. You can also replace a DLL. It is only the FSF's opinion that a DLL is usually part of the same work and not a separate one. Anyway, why should work boundaries not occur inside a single file? if I make a disk image, does the image fall under the GPL just because I installed GIMP?
    – user253751
    Feb 13, 2023 at 18:55
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    Could you take a step back and explain why or even how you saw spreading Free Software philosophy through advertising… as more moderate or acceptable than spreading the Free Software philosophy in a coercive, copyleft-based way, such as the GPL? Feb 13, 2023 at 21:11
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    @RobbieGoodwin Proprietary companies refuse to copyleft to keep their source code secret, while they are culturally tolerant of advertisements. I thought that if we could take advantage of this characteristic and successfully infect proprietary software (social networking, OS, etc.) that are used by a large number of people with advertising for the philosophy, we could reach a much larger audience (although many would ignore it, of course). The Free Software philosophy is for the users rather than the technicians, but we currently lack an effective approach to deliver the philosophy to them.
    – hisaket
    Feb 14, 2023 at 3:16
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    @hisaket They're only tolerant of ads because they bring in revenue. Your required statement does not, so it would simply be seen as an obnoxious attempt to compel speech that's contrary to their business model. Companies would almost certainly see this license as a non-starter, especially once the user complaints started coming in. Even in the best case (for you) scenario, it would be like the cookie consent banners that people started ignoring and mentally filtering out within about a week.
    – bta
    Feb 14, 2023 at 20:13

2 Answers 2


You have essentially reinvented the advertising clause of the 4 clause BSD license:

  1. All advertising materials mentioning features or use of this software must display the following acknowledgement:
    This product includes software developed by [the organization].

While the 4 clause BSD license is accepted as an open source license, the 4 clause BSD license was generally found to be annoying because software using a number of 4 clause BSD packages ended up with a large number of clauses in the advertising. This might be okay if there was one and only one "short propagandistic phrase" which was fixed in the license, but as soon as you allow the authors to choose the phrase, you'll be back in the 4 clause BSD situation.

  • Yes, actually, I am aware of the advertising clause in the 4-clause BSD license, which led me to ask this question, because I think it would be better to reuse a license already invented by someone who thinks like me, to prevent a return of the BSD-like advertising clutter.
    – hisaket
    Feb 13, 2023 at 9:25
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    OP asked about including notices in the user interface, not in advertising materials. This is a very different thing.
    – wonderbear
    Feb 13, 2023 at 16:39
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    I agree with @wonderbear -- the real annoyance was within advertisements ("Imagine if a software system required 75 different sentences... To advertise that, you would need a full-page ad.") Your web browser alone has way more than 75 such notices and license texts, far longer than a sentence, but it's not an issue because they don't have to be included in ads. This question seems to ask that, alongside an unobtrusive copyright notice, you must also include a free-software-is-great notice.
    – apsillers
    Feb 13, 2023 at 17:04
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    I wonder what would have happened if there were a standardized means of publishing acknowledgment lists, and advertisements were required to provide a means by which anyone who wanted to find the acknowledgment list could look it up, and anyone wanting to archive such lists to help ensure that lookups would be possible in perpetuity could do so relatively easily?
    – supercat
    Feb 13, 2023 at 17:29
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    @supercat That would be SPDX, a Software Bill of Materials format. Projects not only need to track license data, but also specific packages, version numbers and hashes, e.g. to ensure components with security vulnerabilities are updated and nobody tampered with the code.
    – user71659
    Feb 14, 2023 at 7:07

The GPL (and related licenses) does something similar.

First, the GPL has a preamble that is basically an advertising statement for the free software philosophy.

Second, it has clauses (in GPLv3 search for "Appropriate Legal Notices"; in GPLv2 look at section 2c) about including information about licensing in the user interface.

This basic idea could probably be adapted to do what you want, but I am not aware of anyone who has already done exactly what you want.

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    This is exactly what I thought of when I read the question. It seems like the OP basically wants a permissive software license with GPL-like Preamble. That doesn't sound impossible, but I agree it doesn't yet exist.
    – apsillers
    Feb 13, 2023 at 17:07
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    One note: I think your paragraph that begins "Second, ..." is explaining why such a Preamble would still be GPL compatible, but it might help to explicitly say "therefore such a term could still be GPL-compatible" in your answer. (I was just confused for a moment because in the previous paragraph you talk about emulating the GPL, whereas this paragraph talks about why the GPL will admit compatibility with this idea, rather than suggesting another way to emulate it.)
    – apsillers
    Feb 13, 2023 at 17:14
  • @apsillers That phrase "Appropriate Legal Notices" appears 4 times in GPLv3. The first occurrence defines it, the second and third require that such notices must be preserved. The fourth is about license compatibility, it says that licenses like OP's idea would still be compatible. I didn't elaborate in such detail because I thought people would be able to search for it themselves.
    – wonderbear
    Feb 13, 2023 at 17:54
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    Absolutely, I only suggest clarifying the intent of each paragraph, i.e., the GPL has a preamble (so you might emulate it in your license) and the GPL has allowances for legal notices (so it will admit yours as compatible; you do not need to emulate this mechanic in your own license to enjoy compatibility). If you think your two intents are clear enough as-is, I won't trouble you further about it; I think your answer here is good.
    – apsillers
    Feb 13, 2023 at 18:05
  • Note however that you (probably) should not copy the literal text of the GPL preamble when composing your own license, unless you get the FSF's permission to do so. They might well grant it, if they like your license, but you ought to ask.
    – Kevin
    Feb 14, 2023 at 0:28

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