Review websites are typically supported by advertising. Some business review websites may also allow businesses to spend for enhanced lists, which do not impact the reviews and ratings. Item review websites may be supported by offering associate links to the sites that offer the evaluated products.
Because of the specialized marketing drive of this type of site, the reviews are not objective.
For example, the UK customer advocacy organization, the Customers' Organization, offers Which?, a website that carries no advertising but covers various services and products, with reviews and ratings often based upon exhaustive independent screening. Another type of review website does not offer free-form content reviews, but instead examines a particular class of items, solutions, or businesses using a collection of pre-defined criteria. One such instance is the Canadian buying website Wishabi, which evaluates business on 42 criteria  and displays the results in a collection of icons. This 2nd type of expert review website has the tendency to offer a better system for relative evaluation, but at the expense of minimized flexibility and richness.