The background to my question is that I noticed that I used the URW++ GPL font exception for my metatype1 (meta)font Oceania, a licensing solution common at the time when I made it. I am now looking for an alternative, because that exception seems insufficient – it is explicitly talking about “Postscript or PDF” files only.
The SIL OFL seems to be a commonly used option, and I tend to go with what’s commonly used except if I have severe concerns. I see that the SIL OFL is considered as DFSG compatible, FSF approved and OSI approved, which seems good. On the other hand, I like to check things for myself rather than blindly accepting the opinion of those organizations.
I personally dislike the anti-commercial spirit of the SIL OFL. The preamble is giving special emphasis to “academic and linguistic communities”. Why not hobbyist, why not amateurs,. why not commercial communities, why not children painting their own letters (perhaps with help of their parents)? Font design should be for everyone, not merely academics and linguists. Condition 1 expresses a fundamentally anti-commercial stance. It is completely unclear to me how a court would interpret that condition. Is a standard “hello world” enough? Does the font have to be distributed together with a program that actually uses the font in some way? Can the program plus the font be sold for more than the value of the program alone? Those a tricky questions are implied by Condition 1 and I dislike that one has to even consider them. I have no issues with people selling the font by itself. Given that, as you say, you don’t agree or disagree with specific interpretations, that leaves much room for courts to go one way or the other. I am thus pretty sure that the SIL OFL is not the right license for me, despite its popularity, or perhaps only for dual-licensing to ensure compatibility.
A different solution would be to use the FSF’s own GPL Font exception, the existence of which I wasn’t aware yet when I did the font. And that’s the solution that I tend to favour at the moment. However, the wikipedia article on the GPL font exception mentions that Redhat has its own font exception in opposition to the FSF’s, Ubuntu has its own font license, and none of them agree very much with each other.
I would prefer a licensing solution that has a copyleft for the metafont, has a copyleft for the hinting instructions as soon as they are above some level of complexity (but with permission for embedding), but has a very permissive, non-copyleft license for the individual curves produced by the metafont. This way using the fonts for eg. a vector logo would be completely unproblematic. But I can’t find a license that matches this. Perhaps I have to write my own, though I am very reluctant to add another license to the zoo.