The "merchant-site-category" field is the category you use in your own store for each product.

For example, let's say you own an outdoor sporting goods store, and you are trying to sell one of your overnight backpacks on Yahoo! Shopping. Your products are currently organized into five outdoor categories on your web site: Cycling, Fly Fishing, Climbing, Camping, and Paddling. The backpacks (by product type) are listed in the Camping section. In this case, the "merchant-site-category" for the overnight backpack would be:

Camping > Backpacks > Overnight

Yahoo! uses your merchant-site-category data (as well as your names and descriptions) to categorize your products into valid Yahoo! Shopping categories when you choose "auto-categorization" or to validate your choices for self-categorization. Please note that the categorization process can take up to 24 hours.

If you wish to categorize your products yourself, please do so by entering the appropriate Yahoo! Shopping category in the "yahoo-shopping-category" field. You should also complete the "merchant-site-category" field. Yahoo! reviews all product categorizations, so it may take slightly longer for your listings to appear on Yahoo! Shopping.