Top Ten Web Design Mistakes of 2003: Love Nielsen or hate him, there’s some good advice here.
8. Products Sorted Only by Brand. Sites that offer many items ought to provide winnowing and sorting, which is a highly useful way to deal with lists and is fortunately fairly common. Unfortunately, many sites only let users sort items by brand. So you can find, say, all Armani products, but not all red sweaters.
I see his site still hasn’t been redesigned, however.