ABSTRACT
During the last decade, the Internet has become an increasingly important mass-communication media touching on all areas of life and providing information concerning health issues. Here the Internet plays two roles: it is a medium of information, and a medium of communication for groups as well as for individuals. The possible effects on individuals obtaining health-related information from the Internet and joining health-related online groups are controversial. Eysenbach and Kohler (2004) classified 4.5% out of 2,985 search expressions, randomly selected from a sample of 298,512 query strings taken from the Metaspy Exposed Web site, as health related. It is estimated that more than 100,000 health-related Web sites exist in the United States (Morahan-Martin, 2004). On a typical day at the end of 2004, 7 million adult Americans went online to get health or medical information and 93 million have used the Internet for health or medical purposes (Pew Internet & American Life Project, 2005). Online, it is possible to attain information about almost every kind of disease, even about those that are extremely rare.
