The difference isn't so much the server, but the third party. You're allowed to modify computer programs (websites) as part of using them. You aren't allowed to then transfer the modified version (see section 117 of the US copyright code).
If you're in control of the server there's a plausible argument that you aren't transferring it. When perplexity is in control of the server... I don't see it. A traditional ad-blocker isn't "redistributing the content to the end-user who requested it" because it's the end user who has ownership over the data the whole time (note: not the copyright, the actual individual instance of the data). Unlike with a server run by a third party there is no third party legal entity who ever has the data.
You could conceivably make "ublock origin except it's a proxy run by a third party and we modify the website on the proxy", I'd agree that that has the same problem as a service like perplexity (though a different fair use analysis and I'm not sure what way that would go).
> I'd also point out that in the U.S., search engines have passed the "Fair Use" test of exemption from copyright — I think it would be very hard to make a distinction between what a search engine is doing (which is on a server!) and what an LLM is doing based on trying to say copyright distinguishes between server vs client architectures.
Well, sure. It's easy to distinguish between an LLM summarizing content and a traditional search engine though (and in ways relevant to the fair use analysis), just not based on the server client architecture.
Disclaimer: Not a lawyer, not legal advice, and so on.
Section 117 is irrelevant — it grants archival rights to end-users for computer programs. It doesn't make claims about servers or legal third parties.
(Although it is relevant in disproving your point: I can pay an archival service to back up data I legally have the right to view, even if the backup is then on their server, and despite the service being a different legal entity than me. And they can give me a copy of it later, too.)
> You could conceivably make "ublock origin except it's a proxy run by a third party and we modify the website on the proxy", I'd agree that that has the same problem as a service like perplexity (though a different fair use analysis and I'm not sure what way that would go).
So, running a local LLM version of Perplexity that does exactly the same thing is legal, but Perplexity is illegal, because "a third party legal entity has the data"?
If you're in control of the server there's a plausible argument that you aren't transferring it. When perplexity is in control of the server... I don't see it. A traditional ad-blocker isn't "redistributing the content to the end-user who requested it" because it's the end user who has ownership over the data the whole time (note: not the copyright, the actual individual instance of the data). Unlike with a server run by a third party there is no third party legal entity who ever has the data.
You could conceivably make "ublock origin except it's a proxy run by a third party and we modify the website on the proxy", I'd agree that that has the same problem as a service like perplexity (though a different fair use analysis and I'm not sure what way that would go).
> I'd also point out that in the U.S., search engines have passed the "Fair Use" test of exemption from copyright — I think it would be very hard to make a distinction between what a search engine is doing (which is on a server!) and what an LLM is doing based on trying to say copyright distinguishes between server vs client architectures.
Well, sure. It's easy to distinguish between an LLM summarizing content and a traditional search engine though (and in ways relevant to the fair use analysis), just not based on the server client architecture.
Disclaimer: Not a lawyer, not legal advice, and so on.