> Also you can't say "we license this as AGPL for non-commercial use". That violates the rights of the user to not have additional restrictions placed on the AGPL. And if you think through the practicalities of how that would work, it's not feasible anyhow.
Good point! (Maybe) to fix this problems, for dual licensing with a non-commercial AGPLv3-like tier and a commercial tier, we would require a "modified AGPLv3" on the non-commercial tier. That "modified AGPLv3" would explicitly prohibit commercial use.
Yes, I was referring to that section. Eventually restrictions on commercial use completely nullifies the AGPL... no one ends up with anything that's AGPL in the end.
Your alternative approach here would work. Maybe specifically a tri-license: non-commercial, commercial, and plain AGPL. For non-commercial licenses, this list mentions some: https://www.gnu.org/licenses/license-list.html
Also consider that the AGPL strongly discourages modifications directly to it. The proper way to "modify" it is by adding extra permissions. Those permissions can come with strings attached (from the original developer only), but any user should be able to discard those terms and choose the original AGPL instead. So instead of dual or tri-licensing you could add permissions that say, you can bypass requirements X, Y, and Z of the AGPL but only if either: (1) you use this non-commercially or (2) you buy a license. But in that event you basically can't have either one of those people sharing their code or it pollutes everything and might destroy the original project. Meaning, not only could a project be forked, but forked as many wildly different and incompatible licenses with the original author having no control of it.
Are you referencing "further restrictions" in AGPLv3's "additional terms"? http://www.gnu.org/licenses/agpl-3.0.html#section7
Good point! (Maybe) to fix this problems, for dual licensing with a non-commercial AGPLv3-like tier and a commercial tier, we would require a "modified AGPLv3" on the non-commercial tier. That "modified AGPLv3" would explicitly prohibit commercial use.
There is a Stack Overflow question asking on how to prohibit commercial use: http://stackoverflow.com/q/3485750/923560