I think jordin's got good one's with his first and second. Might I add:
What size and type of reviews to you appreciate the most? (Type covering the answer of Jordin's first question, size being in average words - Can't forget to keep an eye on what the reviewed think!)
Do you appreciate extremely negative criticism? (Some do, some don't. Good info to be recorded - you can generalize from it).
What do pure 'positive feedback' reviews make you think? (I personally enjoy this type of review a lot, though I prefer negative reviews! Answers to this question could give light on members view of the use of YWS, and their preferences).
Who is the greatest reviewer you know of on YWS? (This would show what people respect in other members. Some people might say 'KatieHalltiner' is the greatest member on YWS because she has more posts than anyone else!' while others might say 'Snoink is the greatest member ever because she has more reviews than anyone else' and others might say 'Rydia is the greatest member ever because she does the best and biggest reviews', and others might say 'Ignorance is the greatest member because she's so nice!' . . . and so on. Good information to have.
For I who am poor have only my dreams I spread my dreams under your feet . . .
. . . tread softly for you tread on my dreams.
We are masters of our silences, and slaves of our words
A big general question like: Why do you review? could do! Although it's a bit straightforward, and people can right away answer that they're doing it for points, there should be something deeper.
-- What is the significance of reviews to the author of the piece? -- How many reviews should one do every day?
Technical questions would also do good: -- How many 1000 word reviews should you do to get x points?
Need some feed? Then read some! Take a look at today's Squills at In the News.
I like Alfred & Jordin's train of thought, as to asking why people review. To go along with that idea, maybe asking what motivates you to review? Some people may only review on review days, or they might be motivated in other ways, such as leader boards, Knights of the Green Room, or when they read a work they've enjoyed reading.
Similarly, asking questions like: do you find reviewing difficult and why. Might give us an overview of typical problems people encounter with reviewing, such as: time constraints/laziness, not knowing what to say/not finding anything in a piece, etc.
This sort of survey thing might help us determine what we need to do in order to address problem areas and show how reviewing can actually be something fun, as opposed to stressful. We've done a reviewing workshop in the past that covered tips & ideas on what to cover in a review, we've also done reviewing tournaments in the past as well. Maybe even asking questions such as whether anyone would be interested in participating in another workshop, or site hosted events and how often they would like to have them.
I like all the ideas stated above! Thought I'd add my own:
What do you specifically focus on when you review? (if you can choose more than 1) - Character - Plot - Style - Grammar, punctuation and spelling - Flow - Other
What would you compare your reviewing habits to? - A hare (lots of reviews in a short space of time, and then a long break) - A tortoise (only writing one or two reviews... but doing so everyday) - A tortare (it varies) - What's a review?