I'll summarize what I know. This is tainted by my partial knowledge (I didn't follow everything), my partial memory and my point of view on the subject.
Stack Exchange started out as Stack Overflow, a questions and answers site for programmers. It then expanded to cover other subjects. See the Wikipedia article for a timeline. When Area 51 started, allowing anyone to propose a site on any subject, one of the first proposals (back in June 2010) was Theoretical Computer Science. The site was proposed for “research-level questions in theoretical computer science”. After a bit of hesitation, with proposals to drop the restrictions on “research level” and “theoretical” (you'll find some of these on CSTheory Meta, and indeed you cited one of them), it turned out that the community indeed wanted a site for research-level questions in theoretical science, as proposed, thank you very much.
As there was demand for a site covering the rest of computer science, there were several proposals for such a site on Area 51. I think there were 4, but there may have been more that I never found out about or don't remember. All but the last one which gave rise to this site followed the same path:
- A proposal is made.
- 5 people vote to close it.
- Before or after the close voted, a discussion happens about the suitability of the site.
- The closed proposal is automatically deleted after a month, as are the associated discussions.
As far as I can tell, there were three reasons why people voted to close the CS proposals:
- There is already a site with “computer science” in the name. Your proposal is an obvious duplicate of this. (Here's a typical example; there were many others.) Now that you've pointed out that the site's FAQ says that it's only for research-level questions about theory, I don't care because I disagree with the existence of a site with these restrictions, there should be a more general CS site. Therefore the CS proposal must not be allowed to proceed, and CSTheory must be forcibly expanded.
- There is already Stack Overflow, whose FAQ allows “software algorithm” questions and “practical, answerable problems that are unique to the programming profession”. This clearly makes computer science on-topic on Stack Overflow. For more theoretical questions, there is also Math Stack Exchange. If you really think there's more to computer science than algorithm and that theory stuff, there are already many sites about computers: IT Security, Super User, Drupal¹, and many more. There is no room for yet another computer-related site.
- Since CSTheory caters for researchers, what remains is homework questions from CS students. We don't want a site for homework questions only, and besides Math and Stack Overflow can cover these questions anyway.²
Back in February 2011, Jeff Atwood made “there's already CSTheory and we don't like them so we won't allow another site” the official answer. This didn't stop other CS proposals, until one finally succeeded.
As for what this history teaches us, I think it's typical of two things:
- the difficulty that computer science has to be recognized as a science. Too many people see “computer” and think spreadsheets and internet and stuff, not science. Mathematicians (and even some computer scientists) look down on computer scientists who pursue less theoretical concerns as inferiors. Non-scientists (e.g. programmers) look down on scientists as ivory tower types, with a simple and firm divide between what programmers do (useful stuff) and what scientists do (useless stuff — all that boring math they crammed down my throat in college).
- Area 51 doesn't work so well, and in particular the way the community decides on which proposals are viable is completely broken. I think there's mostly a consensus about that, but nobody knows how to make it work better. It was clear with the CS proposal that the people evaluating it didn't understand what the proposal was about, and often did not act responsibly (not reading the CSTheory FAQ before making up their mind of what the site was about).
This was an object lesson for me too, in demonstrating that shouting louder is more important than having good arguments. Eventually the proponents of the CS site formed a small but active lobby while everyone else got tired of the subject. Our challenge now is to regain the interest of the people who might participate on the site.
¹ No, I'm not kidding about this one.
² This reason is rather more informed and elaborate than the other two. It didn't have much of an opinion share compared with the other two.