A recent useful feature that I have seen added to Google search is part of the Advanced Search criteria. It filters by reading level. This level has been determined by Google in some magical way (yes, I will read more later) and at the moment only applies to English pages.
My main use for this is when searching for technical references, when I don't want to find the "did you forget to turn the power on?" solution or description.
When you search, you will see the break up of different pages, at their reading levels.