Say someone wanted to know what is the opinion of the Bitcoin community on "On Bitcoin and Red Balloons" - whether what Microsoft has written about Bitcoin is accurate, or did they make some errors on the matter. Would such a question be in scope on this SE, as it could be quite useful to get some respectable opinion on the matter, or would it not be really welcome as it would "solicit opinions" and function as reviews or the like?
As long as the question is finite and answerable and actually pertains to Bitcoin it should be on-scope here. We would prefer questions that can be phrased in the question area itself rather than simply linking to an external source and saying "is this accurate" since we have no control over external sources and whether they remain available or not. If your question is little more than a link, it will probably be closed, though a good description or quotes from the text itself go a long way.
I personally would welcome such questions on Bitcoin SE, as it is easy to have misconceptions about how Bitcoin works and there don't appear to be any way to peer-review Bitcoin-related papers in a away that would be meaningful to the community. The Bitcoin forum would be too unmoderated to function properly in this manner, whereas the Stack Exchange offers a good way to solicit meaningful insights, rather than opinions of community newbies. The main problem I see with using SE for this, is that the answer-reviews could get quite lengthy, but not like we haven't seen that before.