Product feed
Appearance
A product feed is a file containing information about the products listed on your site. Product feeds are used by e-commerce companies to provide information about products in an online store to search engines, product comparison websites, and other similar aggregators of e-commerce information. By sending product feeds regularly you can make sure these sites display the latest pricing, promotional, or other information for your products.
To create this file, all you need is a spreadsheet program or text editor.
Links
Yahoo Product Feed Info http://productsubmit.adcentral.yahoo.com/sspi/us/spec
Google's Froogle Product Feed Info https://www.google.com/froogle/merchants/feed_instructions.html