I've recently been experimenting with ways to provide simpler structured searching/querying to 'normal' web users (i.e. not techies). Sparql/SQL querying doesn't cut it here - we need something simpler.
One approach I've been trying is allowing simple query constraints in with the text search facility. Using the proximity searching capability JAM*VAT then finds a collection of symbols that match all the constraints in close proximity.
E.g. the search: "danny ayers >2005-10-25 <2005-10-27"
..brings back subjects linked to the words 'danny' and 'ayers' and any dates between 2005-10-25 and 2005-10-27 - in this case it finds blog posts made between these dates.
N.B. you may need to tweak the dates a bit in the above example if you're reading this later than october 2005.