media such as television, radio and newspaper because of a shift toward the usage of the Internet for news and music as well as devices like digital video recorders (DVRs) such as TiVo. Online advertising began with unsolicited bulk e-mail advertising known as "e-mail spam". Spam has been a problem for e-mail users since 1978. As new online communication channels became available, advertising followed. The first banner ad appeared on the World Wide Web in 1994. Prices of Web-based advertising space are dependent on the "relevance" of the surrounding web content and the traffic that the website receives. In online display advertising, display ads generate awareness quickly. Unlike search, which requires someone to be aware of a need, display advertising can drive awareness of something new and without previous knowledge. Display works well for direct response. Display is not only used for generating awareness, it's used for direct response campaigns that link to a landing page with a clear 'call to action'. As the mobile phone became a new mass medium in 1998 when the first paid downloadable content appeared on mobile phones in Finland, mobile advertising followed, also first launched in Finland in 2000. By 2007 the value of mobile advertising had reached $2 billion and providers such as Admob delivered billions of mobile ads. More advanced mobile ads include banner ads, coupons, Multimedia Messaging Service picture and video messages, advergames and various engagement marketing campaigns. A particular feature driving mobile ads is the 2D barcode, which replaces the need to do any typing of web addresses, and uses the camera feature of modern phones to gain immediate access to web content. 83 percent of Japanese mobile phone users already are active users of 2D barcodes. Some companies have proposed placing messages or corporate logos on the side of booster rockets and the International Space Station. Unpaid advertising (also called "publicity advertising"), can include personal recommendations ("bring a friend", "sell it"), spreading buzz, or achieving the feat of equating a brand with a common noun (in the United States, "Xerox" = "photocopier", "Kleenex" = tissue, "Vaseline" = petroleum jelly, "Hoover" = vacuum cleaner, and "Band-Aid" = adhesive bandage). However, some companies oppose the use of their brand name to label an object. Equating a brand with a common noun also risks turning that brand into a generic trademark – turning it into a generic term which means that its