When shopping online, the "Narrow your Search" options force shoppers to pigeon-hole themselves into small searches.
If there were checkboxes instead... we could pick RANGES of options, like $101-200 ...and... $201 to 300; OR we could pick specific vendors, like HTC and Samsung (and leave out Blackberry).
Most of the time, I want to shop for a price range which is nowhere near the selections offered... like I might want 'under $500' but all you offer is 0-99, or 100-199, or 200-299, or 300-399, or 400-499, etc., etc. I don't want to have to do multiple searchers in each pigeon-hole so that I can see them all.
Oftentimes, I want to OMIT a vendor... like all smartphones EXCEPT Blackberry... instead, I'd have to search EACH vendor... SO I DON'T EVEN PICK ANY.
And not just price and vendor... but checkbox ALL the 'narrow' options... because I might want either an i5 or an i7 CPU, but not an i3... so I have to do two searches.
Aggravating.... so I just don't. So you lose a sale.