A site where people can compare prices/services for different advertisers usually linked to verticals like broadband or insurance.
Example: In Broadband a customer will visit a site such as Broadband Genie to look for fibre broadband deals. The customer can enter a post code and directly see all deals, across all providers in their area. These types of sites will also secure additional offers that are appealing to consumers in order to strengthen the offers they show.
References:Broadband Genie, Compare the Market, Money Saving Expert