Compariosn shopping sites are products based search engines, which usually allow catalogue submission.
Shops selling items where some comparison is made before purchase, eg. clothing, footwear, household goods (furniture, carpets, electrical), recreational items, personal items.
Retail items not bought on a frequent basis, for example televisions and white goods (fridges, dishwashers etc).
The two major activities involved are: (1) merchandise shopping where checks are made on types of product, prices, advertised promotions and new items offered by competing stores; (2) service shopping where checks are made on the quality of selling and service offered by sales staff of competing stores.
Comparison shopping sites are a type of search engine that allow you to submit information about products; there may be a charge for submission and a charge per click.