Any publication is fine as long as you can provide evidence. In fact the only thing special about publication is that it is a convenient way to demonstrate evidence of the prior art. What could be tricky about e.g. a personal blog post is proving that it was published when you say it was and that time stamps are genuine.

For those who are interested and doesn't know already[0] this is one of the places where blockchains and similar, older technoologies are actually useful: to provide irrefutable proof of knowledge at a given time.

Note however that similar services has been done for years[1] before Bitcoins and blockchains became a thing but since they neither need multi-Gigawatt-Proof-of-Work [2] nor any kind of "Coin" that can be pumped (and dumped) it wasn't cool.

[0]: https://xkcd.com/1053/ (and hi to todays lucky 1/10000! : )

[1]: See here for an article that describes it: https://www.vice.com/en_nz/article/j5nzx4/what-was-the-first...

[2]: but, it kind of works anyway since it would take quite some work to find the majority + the archived ones of a certain days New York Times papers and change the classifieds section.

I'm somewhat sure that prior art requires publication, and not just knowledge.

The internet archive has long been used as evidence for such publication-at-time claims, and they even have a paid service allowing you to trigger snapshots IIRC. There's a FAQ regarding the use of their data in court cases that is somewhat interesting to read.

I know the cryptocurrency community has this absurd notion that nothing without cryptographic proof could or should ever be regarded as evidence. That trusting institutions, people, or processes marks you as a gullible fool, and that the Federal Reserve is conspiracy by private banks to keep the gentile from the levers of power[0].

So this is the not entirely novel situation of crypto being proposed to solve a problem that doesn't exist, and failing due to the lack of (usually: active hostility to) subject matter expertise.

[0] last point unrelated to this specific situation and just included for completeness

> I know the cryptocurrency community has this absurd notion that nothing without cryptographic proof could or should ever be regarded as evidence. That trusting institutions, people, or processes marks you as a gullible fool, and that the Federal Reserve is conspiracy by private banks to keep the gentile from the levers of power[0]. So this is the not entirely novel situation of crypto being proposed to solve a problem that doesn't exist, and failing due to the lack of (usually: active hostility to) subject matter expertise.

It reads like you count me in with the cryptocurrency community.

If anyone else does: don't.

I'm pointing out one single place were blockchain can be useful and then immediately pointing out that it isn't strictly necessary.

Yes, you are free to pay a lawyer and sue to attempt to invalidate a patent using your blog as evidence of prior art. Of course whichever side can afford it, will bury the other side in motions and discovery requests until they win.

Not a lawyer, but as I understand it any publicly accessible publication would suffice. Actually I think any sort of open demonstration of the idea that others can learn from is good enough, but I have no idea how edge cases are handled or precisely how open it has to be.

The sibling comment mentions a good point about the falsifiability of time stamps. If you're particularly worried about being challenged, you might point the Internet Archive at your blog or keep your blog content in a repo that you push to GitHub. For the truly paranoid, consult an attorney.