Shopping search engines, also known as comparison search engines, allow searchers to easily compare products and in some cases compare sites that sell the same products.  As a search marketer, what you care about is that these sites use a Cost Per Click model for buying traffic to your products. Unlike organic and paid search, to include your products in the shopping search results, you use a feed mechanism to send your product catalog entries to each shopping search engine. The feeds for each engine are similar, but each require slight adjustments to optimize descriptions and other ranking factors such as price, shipping and availability.

These are the most important shopping search engines:

  • Google Shopping. While most do not consider it to be an actual shopping search engine, it is one of the larger multi-merchant shopping sites and drives more traffic than true comparison engines.
  • Shopzilla. Shopzilla is the largest true shopping search engine where you can compare the same product from multiple online retailers.
  • Pricegrabber. Another large comparison shopping site, which has a relatively low average cost per sale. In addition, its content is listed in Yahoo Shopping expanding your reach.
  • eBay Commerce Network. Second only to Google for traffic and brand recognition, this site is a good option due to flexibility of bids based on category.  The feeds also are fed into Google organic Search Results to help increased traffic.
  • Nextag. One of the most expensive comparison sites, but according to CPC Strategy’s Research, Nextag has one of the highest merchant conversion rates.
  • Bing Product Ads. Similar to Google Shopping, Bing offers a dedicated shopping area along with ads appearing in the normal Bing Search Results.

If your budget allows, you should get your products listed in every shopping search engine that you can.  However if your budget is limited, Google Shopping and Shopzilla drive the most traffic and have the highest average ROI for merchants.   Pricegrabber is another good option due to its low-cost bidding and reach with Yahoo Shopping. For more detailed analysis of each of these properties you can consult the quarterly Comparison Shopping Report from CPC Strategy.