Do I need a UPC or MPN to advertise my products on the shopping engines?

For many product categories, the shopping engines may require or highly recommend that you include a universal identifier such as UPC or MPN for each product. They then use this information to optimally and accurately place your products on their site. Here's a list of the categories, and notes for each (thanks to Pricegrabber for providing some of this information):

Media (CD, DVD, Books, Video Games)
- UPC is required

Auto-Parts
- Manufacturer Part Numbers are highly recommended, but not required.

Babies & Kids
- Manufacturer Part Numbers are required for Breastfeeding, Strollers, and Car Seats.

Clothing
- Manufacturer Part Numbers are required for Athletic Shoes (Mens & Womens).

Health & Beauty
- Manufacturer Part Numbers are required for Electric Shavers & Trimmers, Electric Toothbrushes, and Health Monitors.

Indoor Living
- Manufacturer Part Numbers are required for Automotive Tools, Hand Tools & Metrics, and Power Tools.

Jewelry & Watches
- Manufacturer Part Numbers are required for Watches.

Musical Instruments
- Manufacturer Part Numbers are required.

Outdoor Living
- Manufacturer Part Numbers are required for: Barbecue Grills.

Sporting Goods
- Manufacturer Part Numbers are required for All Products EXCEPT Accessories, Bicycles, Golf, Ice Hockey, Memorabilia, Paintball, Sports Clothing, Skiing, & Snowboarding.

Consumer Electronics / Computers
- Manufacturer Part Numbers are highly recommended.

Toys
- Manufacturer Part Numbers are highly recommended, but not required.