I posted a question here yesterday and after 6 hours I had less than 10 views. So I crossposted to the Ask Ubuntu SE since it is a bit more active of a site. The question is by no means Ubuntu specific and I genuinely think the answer would be of value to this site. But in order to achieve an answer, I spread my net a little bit wider.
After I crossposted, I edited my post to include some new information and to mention the crosspost. I did this as I have been told before on other sites on the SE network that crossposting is fine so long as you observe proper etiquette and mention the crosspost.
I then received a comment from a user telling me, I'm paraphrasing here, that they had information that might solve my problem but that they would not give it to me because I crossposted. Shortly thereafter, the post was closed as off-topic by a diamond mod.
I have a couple of problems with this.
First, it is not off-topic here. If anything it is off-topic at Ask Ubuntu because it is not Ubuntu specific. I simply went there because it is a bigger site than the Unix SE so there would be more traffic and more chances at a possible answer.
Second, the user's statement that they could help but wouldn't due to a breach of etiquette seems to be contrary to the Stack Exchange's mission statement which is:
...the ultimate intent of collectively increasing the sum total of good programming knowledge in the world
Anytime I've crossposted and got an answer, I've gone back and answered my own unanswered questions so that I can help increase the sum total of good knowledge in the world. None of my previous crossposted questions on any other site have ever been closed.
Third, the close reason included states that, "Cross-posting is strongly discouraged." Discouraged, yes. But outright banned, no. For every post calling for an outright ban on crossposting (1, 2), there is another (1, 2) suggesting that limited use, as long as it is openly declared, is fine. And as long as you go back and spread the knowledge, it is a net positive. This is in contrast to having the knowledge but refusing to share it do to a perceived breach of etiquette which I see as a net negative for this site in particular and the network at large.
In reference to some of the statements in the above linked meta posts, I had honestly not even considered migrating the question. Because, as I've mentioned, it is more of a general Unix question than an Ubuntu specific question. Some of the links in my question reference Fedora, SUSE, and others. So I really feel that it belongs here. But if the knowledge is not available here, getting it elsewhere and bringing it back is of value to the site.
I think what irks me most is that, had I not mentioned that I had crossposted, the user might have shared his knowledge, fixed my problem, and added to the volume of good posts on this site. But I had been told in the past that crossposting is okay if proper etiquette is observed and the crosspost is declared. I did so and ended up getting my question closed.
So my question is this: Specific to Unix SE, is crossposting outright banned here? If so, I simply won't mention it again. Or do others think as I do and that obtaining good answers elsewhere (when they cannot be obtained here in a reasonable amount of time) and bringing them back here increases the value of the site so long as it is done in an open and transparent way?