You can't really put ArXiV and "traditionally prestigious sources" in the same sentence. Any crackpot can (and does) post on ArXiV.
The reason why I'd be more comfortable citing a paper on ArXiV than a random web page (as a mathematician):
1. ArXiV is the archive for papers. You put something there, it's not going away. You can't even remove your own paper once you make it public there[1]. It's a reliable place I can refer people to.
Personal websites? Well, my own very reliable academic web page has been removed by sysadmins without notice after graduation because "we don't maintain accounts".
2. Unrelated content. ArXiV won't have it - unlike, say, the 4chan thread in question. Do I really want to explain to people that I wasn't citing getting "14 * 14! derps out of the way"?. Not to mention ads, memes and NSFW content - which is also there[2][3]
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The other reasons are less important, but are still valid:
3. Presentation. Something on the ArXiV probably is formatted and structured like a readable paper; there are baseline expectations. Reading someone's scratchwork is borderline painful, and a proof on a webpage is usually just that.
Compare [3] to a rewrite[4] - which one is easier to understand at a glance?
4. Reputation. This is different from "traditional prestige". The reputation of ArXiV is that most of the people who do serious work put it there. Most of the people produce nonsense (possibly including yours truly) also put it there, but the probability of any work having been done by someone who is willing to put effort into it goes down dramatically if the work is not on ArXiV.
5. Signaling. Since it's so easy to post there, any work not ArXiV is signaling "I don't care about my work being available to other people in the field". Why one read something that the author doesn't want them to? If they did, they'd put it on the ArXiV.
6. Attribution. A result on ArXiV makes it easy for me to attribute the result to someone. A thread on 4chan? Do I attribute it to everyone who participated? A single anonymous author?
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In short: people give credit to blackboard scribbles and napkin proofs that came out of discussions at conferences, but you won't see "4th beer coaster, such-and-such conference banquet, 2018" as something that people cite.
A proof on 4chan is somewhere in the same category.
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The disclaimer here is that this applies mostly to new results in mathematics. Old results are not necessarily available online, and often we don't have a choice. Practices in other fields might be different.
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[1] https://arxiv.org/help/withdraw
[2]https://warosu.org/sci/thread/S3751105#p3751197
[3]http://4watch.org/superstring/
[4]https://docs.google.com/viewer?a=v&pid=forums&srcid=MTUwMTUx...
What kind of work was that?
Post: http://james.pirruccello.us/index.php?title=Gamma_gap
Paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4668045/
Why would a footnote be considered less credit than something in the list of references? It's pretty common in my field to use footnotes to give credit to other researchers for ideas that arose in an informal context, e.g., "I thank A. Zee for pointing this out". Indeed, the question of whether prose footnotes are at the bottom of the page rather than displayed intermixed with citations to published sources (as in Physical Review Letters) is just a stylistic choices that varies by journal.
Obviously unpublished sources can't easily be counted into automated citation tracking systems for technical reasons, but if the author wanted that they could publish something (or, e.g., put it in a free repository like the arXiv).
I added the Google Books Ngrams example slightly later, but: People _do_ publish papers about their data, and their citation counts are often extremely low, because research users continue to use footnotes instead.
In the OP case, the 4chan author was anonymous.
EDIT:
> People _do_ publish papers about their data, and their citation counts are often extremely low, because research users continue to use footnotes instead.
Are you talking about researchers not giving credit for pure data sets? That is a really very different topic.
Let's continue with the Google Ngrams example. All I had to do was search Google Scholar for "Google Ngrams" to find easy examples on the first page of results, like this one: http://www.aclweb.org/anthology/W14-1611
The paper is written by famous Stanford researchers, and they do not cite a single author of their data. Just URLs in footnotes.
This also happens to my research (ConceptNet) all the time. The fact that you haven't noticed it doesn't mean I'm making it up.
I don't see why you think researchers not giving credit for data is a different topic from what I brought up. What I said was, researchers in my field are in the habit of not giving credit for data, and instead they have adopted the convention of using half-assed footnotes with URLs in them, which is not appropriate credit. I speculate that one reason for this habit is that data often comes from inconveniently non-academic sources and would look bad in the bibliography. The habit is so pervasive that authors remain in the habit even when a paper exists.
For what it's worth, I agree with your criticism.
If they didn't, but they do have a web page on the thing, then give them credits in the currency of the web: links.
GP has a point: if the creators want scientific credit, they can easily get that via ArXiv (or, of course, a peer-reviewed publication). If not: increase their PageRank.
Is your field Quantum Field Theory?
Such is academia, I guess. It’s more important to get “prestige” than to properly cite someone else’s work-where it was published should not matter.
Unlikely. I can't speak for everybody, but I can speak for myself, and I would be extremely hesitant to cite a random webpage in a journal article for several reasons:
1) It can change. ArXiv has versioning, but even so, this is still a problem. You cite something, and months later you go back and find the thing you cited says something slightly different.
1b) It can disappear. Again, less of an issue for ArXiv, but a big problem for any other website. Linkrot is real.
2) There's probably a better source. Maybe in this example a 4chan thread is the original provenance of an idea, but 99 times out of 100, there's a better, original source for the idea.
3) There's no peer review. Peer-review is not a pre-requisite for publication, but if you don't have it, it just makes people more skeptical of your results.
4) It's perceived as lazy. This is closest to your point (i.e. prestige), but not the same. Like it or not, if you cite informal sources in a paper, people start to wonder about the rigor of everything else you do. It's an intangible, but when you're trying to get papers accepted, intangibles count.
Basically, citing a webpage is risky. You avoid it if you can.
Archive.org is not a solution to this problem. Nobody is going to go fishing in archive.org for a citation that has disappeared. Even if you have the URL, what is the correct date to use?
There are just practical problems with link citations, and you don't need to invent malevolent intent to understand why researchers are reluctant to use them.
What makes you say this? Citing anybody does little to increase your personal prestige. I think the issue has more to do with 4chan not being peer-reviewed, and the proof being so recent that few papers have yet been written.
On the contrary, citing a hot new thing is what academics do best.
The first paper I looked at for an example (at the top of today's "Recent" papers in PRD), cites three arXiv entries, out of 91 references. https://journals.aps.org/prd/references/10.1103/PhysRevD.98....
Successful peer review in an upstanding journal is a signal of relative reliability and importance, but it is not the arbiter of usefulness.
I have seen this in computational linguistics where people frequently don't cite their data sources, which often come from outside of the field or outside academia altogether. Instead they put a link to a webpage in a footnote, which does nothing for assigning credit.
Reviewers don't take anyone to task for it, because they do that too.
For a while, there was a collection of multilingual word counts over OpenSubtitles that everyone was using, and you would acquire it from the OneDrive of the pseudonymous blogger "Hermit Dave". Many people put the link to his blog in a footnote, but I think I was the only person to come up with a citation for (Dave 2011).
People don't even cite Google Books Ngrams and that's got a real paper [1].
[1] Lin, Y., Michel, J.-B., Aiden, E. L., Orwant, J., Brockman, W., and Petrov, S. (2012). Syntactic annotations for the Google Books Ngram Corpus. Proceedings of the ACL 2012 system demonstrations, 169-174.