They mention it in one of the lines of this blog, but apparently this individual (perhaps with the help of others, it wasn't clear) has come up with two of their own software licenses, with a website and everything. https://guide.licensezero.com/ > The Prosperity Public License (Prosperity) works a bit like a Creative Commons NonCommercial license, but for software. Prosperity gives everyone broad permission to use y…
> However, I always found it a bit strange that there were dozens of variants of the MIT and BSD license out there, but aside from the GPL and MPL no other popular license really took up the mantle of copyleft, aside from perhaps the old Sleepycat license. Fundamentally, copyleft can only be instantiated once. No two distinct copyleft licenses as we know them can be compatible with each other without jumping through…
That's true of GPL-style copyleft, because it was designed quite intentionally to be a network-effect-leaden singleton. We say "GPL-compatible", but it's more accurate to say "GPL-submissive". The difference was felt very directly by the Eclipse folks in the run up to EPLv2.
But there's nothing about share-alike terms that require that stricture. The Parity license that I mention in the blog post takes a different tack. Have a look at its rule about how to contribute back: https://paritylicense.com/versions/7.0.0.html#contribute
A developer building on Parity code could choose to license their work on weaker copyleft terms.