[cabalamat]

> strongly suggestive that they have been trained on copyrighted materials

Given that everything -- including this comment -- is copyrighted unless it is (1) old or (2) deliberately put into the public domain, this is almost certainly true.

[rusk]

Isn’t this comment in the public domain? I presume that’s what I’m doing when I’m posting on a forum. If somebody copied and pasted something I wrote on here could I in theory use copyright law to restrict distribution? I think the law would say I published it on a public forum and thus it is in the public domain.

[taormina]

Why would it be in the public domain? Anything you create, under US copyright law, is the opposite of being in the public domain, it's yours. According to the legalese of YC, you are granting YC and YC alone a license to use the UGC you submitted to their website, but if anything, the YC agreement DEMANDS that you own the copyright to the comment you are posting.

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[ANewFormation]

Another example of this is people putting code, intended to be shared, up on e.g. Github without a licence.

Many people seem to think that no licence = public domain, but it's still under strong copyright protection. This is the point of things like the Unlicense license.

[graemep]

> If somebody copied and pasted something I wrote on here could I in theory use copyright law to restrict distribution?

Yes you could, unless you agreed to forum terms that said otherwise, fair use aside. Its the same in most jurisdictions