[AlbertCory]

> "a personal diary would work in principle, but you'd need to somehow prove that you wrote your thoughts down on the date and didn't forge it after the fact"

Patent agent here, not patent lawyer. (that means I passed the patent bar exam and could write your patent, but could not sue anyone over it.)

Wrong, wrong, wrong. Prior art has to be "published" (and there is a whole body of case law about what that means). Maybe you are thinking of the old "first to invent" rule?

[ska]

This is correct, although published is pretty broad it doesn't include everything under the sun.

The real problem is that the patent examiners are not in general required to look at the whole breadth of what is published, just what is in the patent databases.

As a result there can be clear prior art, but unless it gets fed in during the review process, the practical way to resolve that is likely to end up in court, and likely to be expensive.

Of course often "clear prior art" isn't too. Hence the process to sort it out.

[AlbertCory]

Interesting side note about non-patent prior art (by the way, the examiners do, most of the time, look for it):

I was told that a proposal to require the examiners to use Google was rejected by the union: if you're going to require us to do more work, then you have to pay us more.

This was back in 2012 or so. I have no idea if now they have to use Google, but they only get about a day and a half on each patent (again, this is old data).

[ska]

> (by the way, the examiners do, most of the time, look for it)

Sure, but usually superficially (and not, I think, required); which is fair - you can't practically require the patent examiners to have the kind of breadth and depth necessary to have a good feel for this.

[AlbertCory]

One more point about this: the date on the publication isn't necessary the effective date. If it's a journal that says "May 1999" that doesn't mean the date is May 1. It would be the date that it became available to persons in the art.

Getting a librarian to say "yes, we cataloged it and made it available on May 5" would be pretty strong. Or a Wayback Machine archive from May 2.

[lamontcg]

Ah okay didn't know that.

Still I think I've been deposed (I got grilled by an actual hostile patent lawyer) before over an old Usenet post I made in the late-90s (that was really more of a "showerthought" in the middle of an flamewar) that was being used to attack a patent.

[nightpool]

Yes, the rules changed in 2011, as part of the America Invents Act. https://en.wikipedia.org/wiki/First_to_file_and_first_to_inv...