AGPL is not the same as plain GPL. The vast majority of the code with a licence from the GPL family is not AGPL, but GPLv2, GPLv3 or LGPL.

I understand the reasoning behind AGPL and on the surface it seems like a good idea, to stop the parasitic behaviour many have towards FOSS. But there are many situations where you have very legit reasons to avoid it. Even in this case, AGPL would put you in a delicate position where you need to immediately disclose the changes you made without respecting the non-disclosure period for mitigation.

It's a licence that tries to solve the problem of the GPL going obsolete when many companies no longer distribute software, but rather services based on the software (like Google or Facebook) and they can basically get away with not giving anything back at all to the community work they built upon. But this is very hard to regulate and as a result AGPL is often so cumbersome that AGPL-licensed code is strongly avoided, and it's also extremely hard to enforce when the service simply doesn't release any code or software.

It is not true that AGPL is incompatible with responsible disclosure. Responsible disclosure timelines mean that the source code would be published long before anyone had time to complain about the source not being available.

Enforcement is hard, but AGPL is strictly stronger than GPL which doesn't evenninvitr enforcement on sharing server code.

Yes, many companies avoid AGPL software. That isn't a problem for AGPL-leaning authors, that's the point.

Even if (probably) no one has time to complain about it, you'd still technically be violating the license by withholding code, right?

Probably. AGPL says you need to "provid[e] access to the Corresponding Source from a network server at no charge, through some standard or customary means of facilitating copying of software", and GPLv3 also seems to require digital distribution of software to include immediate source access. GPLv2's source requirement, on the other hand, can be satisfied by a "written offer" to provide the source no matter how the binary is distributed; I think this is (along with apathy) how Apple gets away with taking months to publish GPLv2 sources.

That exposes whoever does this to uncharted legal territory.

There are many reasons why AGPL is used in extremely few projects of any relevance, compared to other GPL licences, or BSD, MIT, etc.

And if OpenSSL had been licensed with a GNU Affero license, we'd all be running something else.

I severely question the enforceability of the AGPL. If they're not distributing they don't need to accept the license in the first place.

AGPL is based on modification rather than public performance or use. You don't have permission to modify copyrighted things by default so if you do modify, then you either comply with the AGPL or violate copyright law.

You can modify copyrighted things, you just can't in general copy your modified version.

Because a number of court cases have sided with the interpretation that "copying bits into RAM for execution" is itself governed by copyright law, in practice you wouldn't be able to use your modified software without breaking copyright. This is why software licenses are "needed" -- lacking some kind of limited license to make copies, execution of software isn't permitted.

Usage licenses are enforceable. At least in the US for sure, and the DMCA builds on that.

Now, to prove that someone is running AGPL software and that they have modified it, that seems pretty hard in many scenarios.

So does this mean users don't need to accept EULAs?

EULAs are largely a farce but in theory you have to accept the EULA to accept the software. As far as I know GPL/AGPL comes in at a different point entirely.

Please research what the "L" in "GPL" means.

http://www.gnu.org/licenses/gpl-3.0.html

Software is protected by copyright by default, meaning you can't make a copy. A license is a limited waiver of copyright that grants permission to make a copy, if the conditions of the license are met.

You're not the one making a copy when you're just accepting the software to run.