Comparison shopping engines collect product information, including pricing, from participating retailers and then display that collective information on a single results page in response to a shopper's search query. In this way, shoppers can compare each retailer's price, shipping options, and service on a single page and choose the merchant that o

Search engine marketing (SEM) is a form of Internet marketing that involves the promotion of websites by increasing their visibility in search engine results pages (SERPs) primarily through paid advertising.