Contextual advertising primarily enables an advertiser to display ads based on the interests or commonly accessed subject matter of the user. Contextual advertising works when a visitor enters a webpage — by using the content, context, keywords and subject matter of the website, the ad networks display ads that are related to it. For example, on a website about television, the contextual advertising will most likely display advertisements from TV manufactures, suppliers, online electronics stores, television programs and similar products and services.