If I use some MIT licensed dependency to power a service at work, I don't beg permission from the maintainers first

While agree that it would be nice from the Substack to give credit to Ghost, they are not required to do.

It's unfair to complain about Substack doing exactly what they are explicitly allowed to do by the company that released Ghost under that specific licence that they choose to.

Yes I agree it's unfair to complain, and I don't think Ghost is complaining (at least I don't see complaints from what John tweeted). It's more about "giving credit where credit's due" I think...

Because AGPL probably would have made it a no-go for substack to use. They seem to genuinely want to collaborate: https://twitter.com/JohnONolan/status/1602330416643702784

Why would AGPL have made it a no-go for Substack? Also, it looks like Ghost wants to collab but there's nothing from Substack in the Twitter thread you linekd?

IANAL but I think integrating AGPL code would affect the license of the rest of the codebase too: Substack would be forced to release the rest of their codebase as AGPL too. This is why AGPL is considered a "viral" license.

> Ghost wants to collab but there's nothing from Substack

Substack doesn't have to "collaborate" do they?

Because AGPL infects their entire service. You'll be hard pressed to find any commercial service adopting AGPL projects. Even the GPLv3 is often immiscible with commercial services. At least GPLv3 can be contained to only part of your stack.