I'm not sure what the status of the discussion is on our domain name. I propose that it have a .edu extension. See my blog post for reasons why.
.edu domains were intended use as a name space for educational institutions.
In practice, its primary use is for universities.
The top-level domain is now officially restricted to "accredited post-secondary institutions and organizations that are accredited by nationally recognized accrediting agencies." (citation).
Stack Exchange does not qualify nor is it intended to meet any of those criteria.