shopping comparison site - definition

Although known by a number of other terms, most notably 'shopping search engine' and 'price comparison sites', these are sites that will search for specific products, or categories of products, that are available from online traders. Although they act as a search engine, to call them search engines can mislead users. Generic search engines (Google, Yahoo! etc) will include all web sites in their organic listings. The 'shopping' search engine, on the other hand, is limited to those sites that have not only agreed to be listed, but reward the search engines if users follow links from the listings to the store (normally in a pay per click business model). The shopping search engines look not only at the sites of individual sellers, but also at those sites which conduct their own searches. Popular in the latter category are airline flights, holidays and car insurance, where the searcher need only enter purchase details. For example, on a comparison site the user enters the date and destination of a flight and the search would check multiple airline sites using those details - so saving the user from entering the same details on a number of individual airline's sites.

For the online trader, using comparison sites as part of their online marketing mix can be a sound business model, and sites can be optimized so as to appeal to the comparison search engines. Although the comparison sites' 'commission' must be accounted for in any product pricing policy, the fees can be offset as marketing costs as the comparison site is, in effect, doing the online marketing for the vendor. Some comparison sites go further than simply listing results and offer review facilities for products listed. In these cases the site becomes an amalgam of a portal and a search engine.

Whilst a number of shopping comparison sites are popular with users for the service that they provide, there is a drawback to the concept. A number of faux-comparison sites have sprung up that seek to take advantage of pay per click agreements with little or no commitment to consumer satisfaction. Often hosted on intuitive domain names, such sites will concentrate their efforts on gaining high search engine rankings, often by using black hat search engine optimization methods. These pseudo comparison sites can be frustrating to search engine users (and the search engines), because they can fill search engine results pages in detriment to the organic listings of genuine retail web sites.

this definition is taken from
Key Concepts in e-Commerce