After my experiences with the Digital Preservation and LIS stack exchanges I am very wary of using them as a platform. I'd agree with others comments that they have far too puritanical and stringent requirements for the kinds of discussion people wanted to have. Beyond that, the kind of activity the stackexchange folks want to see on these boards to meet their needs was a good bit beyond what our communities were going to generate.
On some of the National Digital Stewardship Alliance calls there has already been some preliminary discussions of standing up some kind of digital preservation discussion forms (likely running something like http://www.osqa.net or Vanilla). In a related sphere, digital humanities answers seems to have made a good run at this approach (http://digitalhumanities.org/answers/). If anybody is particularly interested in this, feel free to ping me off the list ([log in to unmask]) and I can make sure put you in the loop on discussion of setting up a digital preservation/stewardship online Q&A forum.