Using the Browse Category box on the left helps you find stuff easily and quickly. Here's what you can do:
Drill into specific categories and then "bounce up" one category by clicking the "up folder" link
Clicking the icon allows you to add that category to your "My Categories" list (explained below)
By setting up your "My Categories" list, you can customize your own list of shopping categories (you hand select them). Then, on the home page or in the jump menu at the bottom of the category box you can select "My Categories" and see a single listing display of all ads from your favorite categories.
At the bottom of the Browse Categories box is a jump menu that lets you skip to one of the major market categories.