Prediction markets if successful may ultimately have millions of worldwide with a wide variety of backgrounds. I agree with 5chdn about the "why" component of the LMSR question being likely to start opinionated discussion. However, I believe that economics, game theory, psychology, statistics and finance (in addition to blockchain technology and Ethereum ...
Asking how things work, e.g. how does exchange X choose which orders to fulfill? Why doesn't this trading code work?
Any thing suggesting or asking for a view on valuation of something, e.g. what do you think will happen to the price of Y?
Things related to customer service, e.g. Why can't I login to Z?
Today there was at least two questions in the review queue about withdrawal from two different exchanges and about the fact that the tx is not visible on Etherscan.
I guess they should ask the exchanges but they probably did and as we all know they don't answer, they arrived here.
But if we always answer these questions, why would the exchanges answer their ...
General personal feeling: Yes, because it is fully operating on top of the Ethereum stack. Here is the related tag: augur, 7 questions asked this quarter.
Going through the example questions with highest score:
Are there any hardware wallets capable of storing REP? 
Yes, REP is a token on the Ethereum platform, valid question and well on-topic....
No. From our off topic close reasons:
"Questions asking us to recommend or find a book, tool, software library, tutorial or other off-site resource are off-topic for Stack Exchange as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it."
I closed that thread.
Since all relevant information for learning Ethereum should be freely available on line, questions looking for particularly good free and online sources of material should be on topic. I personally love when stackexchange is able to not only answer a question but provide a somewhat curated index to more reading materials.
Inviting commercial discussion is likely to cause a lot of chaos if the average ICO Slack is anything to go by. However it seems crazy to ignore the fact as it is pretty important part of the ecosystem. Perhaps there could be a featured question in the sidebar, similar to the wallet question, for "How do I acquire Ether?" that is kept up to date with the top ...