Keyword advertising refers to any advertising that is linked to specific words or phrases. Internet search engines such as Google, Yahoo!, or Microsoft’s Bing generate significant revenue from the sale of keywords to trigger online advertisements that appear on search engine results pages. These advertisements typically relate to search terms entered by Internet users and appear as “banner” advertisements on the top of the Web page or “sponsored links” that are displayed on the right column of a Web page or before relevant search results; such Web ads, if clicked on, direct the user to the website of the advertiser.