|This article does not cite any references or sources. (November 2007)|
A product feed is a file that contains all information about the products of a specific company or companies in the e-commerce industry. Product feeds supply the content that is presented on many kinds of e-commerce websites such as search engines, price comparison websites, affiliate networks, and other similar aggregators of e-commerce information. In some cases they are generated by the online retailer and in some cases the information is extracted using web scraping or harvested web harvesting from the online shops website.
Product feed applications 
Product feeds are an integral part of online live scores, sales and marketing, particularly in the case of online retailers with many different products or with products that are described by many different attributes, or in industries in which pricing and availability frequently change.
Product feeds are used within a variety of online marketing channels that help shoppers locate the product they wish to purchase and drive the traffic to the retailers' website. These marketing channels include:
- Price comparison websites - Feeds are the product descriptive content needed to run sites that compare pricing (price comparison websites), attributes (mostly in vertical search portals) and availability.
- Paid search affiliates - PPC campaigns use API's that receive a range of attributes within product feeds to determine campaign keywords and bidding.
- Affiliate networks – affiliate networks funnel products though their platforms from merchants to affiliates.
- Marketplaces – receive product feeds from their big merchants (eBay and Amazon for example).
Feed formats 
- Google base supports tab-delimited text format and various XML formats including RSS1.0, RSS2.0, and Atom feed format.
- Other product listing sites use proprietary formats that are either plain text or XML format.
- Emerging RDF format: Semantic web standards such as RDF are taking root. It is expected product feed will soon adopt this new web standard.