Twurdy is a new (beta) search engine which I first read about on Larry Ferlazzo's excellent blog. After giving it a try it kind of reminded me a cross between Nettrekker and Google because it gives you results based on read ability levels. Any user of Nettrekker will be very familiar w/ how this is done.
Below is an example of results based on the term, semantic web.
Give Twurdy a try by clicking here.