Just because there are grey areas doesn't mean there aren't also clear cut cases that are ruled out.

If I publish a book as CC-BY-NC you can't turn around and offer it verbatim on Amazon for some fee.

This is useful, and the use of NC in the context of text and media strikes me as quite different to the case for software.

You are correct that there are also cases where use is clearly commercial. Simply selling the licensed work is one although I expect the sort of person who does that doesn't really care much about the license.

Another is probably things like advertising but if the organization has any sort of legal department, they're probably going to want to confirm that you have rights to the work in question.

And then, as I say, there's a vast middle ground about which different people have differing strong opinions.

It looks like your example [1] was actually rather clear cut based on the actual use of the work and case law quoted in the court decision.

I think in most cases it is actually clear what "non-commercial use" looks like.

It did spend four years going through the legal system even if, as a layperson, it seems clear cut and a dumb case.

My primary interest is using photographs and I can pretty much guarantee that almost any use I might have beyond something like wallpaper on my personal computer, some number of people would argue is commercial because it has some connection, even if tenuous, to either my day job or other businesses.

The time the legal system takes to settle a case is another issue as is the reality that anyone can argue anything.

What is commercial and non-commercial has to be judged on each specific case's merit, which obviously makes general discussions difficult beyond broad definitions, but in general it is not a big grey area.

The grey area is massive. Take using photos. What if I run ads or have affiliate links on my blog? What if I'm a US not-for-profit that has $10s of millions in revenue? What if I'm giving a presentation at an industry event that I'm not being directly paid for but it's essentially part of my job?

I could go on but I guarantee that if you surveyed the readers of this site many people would answer those questions differently.

Effectively, if a lawyer were making the call of whether a particular use was OK, they'd tell you just not to use it because no use that you'd be asking a lawyer about is clearly OK.

> What if I run ads or have affiliate links on my blog?

FWIW, in Germany that would indeed make it a commercial endeavor.

It gets even weirder with copyright, being part of a torrent swarm as uploading part has regularly been ruled as "commercial distribution".

These are specific examples, and as mentioned there are an infinity of cases.

I am not sure they are grey areas. For example, in general anything you do as part of your job at a commercial enterprise has a commercial purpose.

Well, see, I'm reasonably comfortable with using NC so long as I'm not selling or being directly paid for something. Otherwise, pretty much everything I have in public is associated with my job at a commercial enterprise or other business in some manner and I effectively can't use NC for anything non-trivial. So, without surveying the rest of HN, we already disagree on a wide swath of use and probably wouldn't change each other's minds.