Does anyone here feel that this site is helpful? I do, but is it Bitul Torah? Because you could always go look up the answer in a sefer and get more schar (reward).
For questions that you could look up in a book, and you know what book to look them up in, and you have access to that book, you should go look them up!
However, there are many questions and many people for which these conditions will not be met.
mi.yodeya is intended to be a tool for certain situations, not a replacement for regular Torah learning.
For examples of questions that I feel are some good examples of the site being useful, please see the Question of the Week series (which has been on break for a little while) on lo.yodeya, our site news blog.