I am currently teaching an ESL class and we were talking about using Google Advanced Search . One of the students showed me that a user can now sort results by reading level.
After a little more research, I found that "the breakdown isn't grade- or age-specific, but reflects the judgments of teachers as to overall level of difficulty. Roughly speaking, "Basic" is elementary level texts, while "Intermediate" is anything above that level up to technical and scholarly articles, a la the articles you'd find in Scholar."
Try this new option and see what you think -- it's exciting, especially the idea that a student brought the feature to our attention!