I am starting this discussion because I truly believe that a Q&A site related to economics and econometrics can be a success. Right. So why the first attempt failed?
I believe that not targeting the undergraduate level, and instead opting for the professional academics and graduate-level students may had something to do with it.
Economics is not a scientific discipline where quick-exchanges between scientists can work. It is as much philosophy as is hard quantitative and mathematical method, and research-level questions sometimes look almost as a research paper in the making, not suitable for a Q&A site.
Moreover, distancing the undergraduates eliminates one of the main reasons why people volunteer their time and knowledge in order to answer other people's questions: for the psychological reward of teaching (and the lowly reward of showing-off). Encouraging undergraduates to participate will have a larger potential to lure in graduate students and even professional academics that will answer the comparatively simpler beginner questions (something that will also present a challenge for them since the form of the communication itself demands a compact yet accessible answer). It happens in other sites, like the math.SE site. And it will obviously be beneficial for the undergraduate students. Which have more questions than anybody else.
In a nutshell, the site should be a meeting place mimicking the real world -where professors teach (and show-off) by answering questions, graduates exchange info by Q&A between them and hone their skills (and show off) by answering the questions asked by the undergraduates, which in turn show off by answering each others questions (being an economist, I don't have any reservation to explain peoples' actions as based on selfish and rather... not highly looked-upon incentives).
And by all means, it should include econometrics. Econometrics is to statistics what finance-economics is to economics : a sub-discipline with so many peculiarities that it has essentially branched-off.
My approach then can be summarized in the following name for the site:
"Α Q&A site for those who study, teach and research economics and econometrics."
I could of course start the proposal right away, but since there is a history (and contrary to the tendency in economics to ignore history), I thought it would be best to try to generate some discussion first (call it "definition in beta").