I was in Portland last week-end, attending a class in Print and Electronic Reference. Our guest speaker was Caleb Tucker-Raymond, the Statewide Digital Reference Coordinator of L-Net , Oregon's on-line reference service. Users are provided the opportunity to chat or email their questions.
A good majority (about 60%) of the users are grade K-12 students. (You can find more statistics about L-Net here .) It would be interesting to find information about what percentage of teachers are aware of, use, and encourage their students to use this kind of reference help. See this for a discussion about students as digital learners and this for a list on YALSA about how libraries can engage their younger learners.