> If someone uses my work to earn any money, then it's commercial.
it really is that simple. It's meant for creative works, but not just; if i make a song and license it CC-NC, you can't use it in a video if that video gets ad revenue, patreon, snail-mail donations.
> Meaning "done for the sake of financial profit" (of art, etc.), "prepared for the market or as an article of trade" is from 1871.
It is trivial, unless you are looking for loopholes to get around licensing.
Is it fornprofit if I use it and somewhere in a small note on my website it has a way to give me a tip?
It's trivial to come up with more such cases.
And you being fine with my usage, doesn't mean I can rely on it.
And then let's go international.
In case of doubt the answer is to avoid it, which can be fine and match the author's intention. However it can be nom-trivial.