The website Academia.edu, which is like a Facebook for researchers and nerds, has recently (I think today, actually) added the option for Q&A for the entire site. Similar to status updates, one may ask a question and tag that question with particular research interests (i.e., musicology, New Testament, evolution, etc.). That question becomes visible to those who have those research interests listed on their profiles, thus enabling them to respond to the query.
If you are a student interested in a particular area (or several areas) of study, consider checking out Academia.edu. It's always interesting to see what others think about the things that interest you. I have an account there (link at the left of the blog page, under the "Stalk Me At" section) if you would like to see an example of what one of their pages looks like. It's free, it's simple, and it's useful.
Did I mention that it's free?