摘要：Objectives . We analyzed the content and characteristics of influential health blogs and bloggers to provide a more thorough understanding of the health blogosphere than was previously available. Methods. We identified, through a purposive–snowball approach, 951 health blogs in 2007 and 2008. All blogs were US focused and updated regularly. We described their features, topics, perspectives, and blogger demographics. Results. Approximately half of the bloggers in our sample were employed in the health field. A majority were female, aged in their 30s, and highly educated. Two thirds posted at least weekly; one quarter accepted advertisements. Most blogs were established after 2004. They typically focused on bloggers' experiences with 1 disease or condition or on the personal experiences of health professionals. Half were written from a professional perspective, one third from a patient–consumer perspective, and a few from the perspective of an unpaid caregiver. Conclusions. Data collected from health blogs could be aggregated for large-scale empirical investigations. Future research should assess the quality of the information posted and identify what blog features and elements best reflect adherence to prevailing norms of conduct. Health care consumers, patients, and caregivers use the Internet to search for information about diagnoses, physicians, treatment options, and medicines. 1 , 2 They also search for support from virtual communities and post advice about managing their conditions. Health practitioners also rely on the Internet to search for information and to communicate with patients and colleagues. The role of the Internet in health care has grown considerably with the evolution of the World Wide Web, now commonly referred to as Web 2.0. Cormode and Krishnamurthy explained that the “essential difference between Web 1.0 and Web 2.0 is that content creators were few in Web 1.0 with the vast majority of users simply acting as consumers of content, while any participant can be a content creator in Web 2.0 and numerous technological aids have been created to maximize the potential for content creation.” 3 User-generated content, the hallmark of Web 2.0, is responsible for the remarkable growth in health-related content on the Internet. This is reflected in tools ranging from Twitter to social networking sites to wikis. The blog (short for weblog) is the quintessential Web 2.0 application. A blog is a Web site containing dated entries, or posts, presented in reverse-chronological order. Blog features commonly include archives (previous posts, typically grouped by month and year), a blogroll (a list of recommended blogs), and a reader comment section. The term blog was first introduced in 1997 to describe a log of links that chronicled visits to various Web sites. 4 Blogs once required programming knowledge to create, but with the emergence of free software such as Blogger and WordPress, virtually anyone with an Internet connection can create a blog. Not only are these software programs free and user friendly, allowing for easy posting of text, audio, pictures, video, and links, but they also provide the servers that host the blogs. 5 The popularity of blogs should not be underestimated. Data show that between 12.0 and 26.4 million Americans blog and 57.0 to 94.1 million are blog readers. 6 , 7 Blogs that focus on health care (whose exact number is unknown) have the potential to provide interactive support networks for caregivers and patients, generate real-time discussions about health news or policy, extend social and political mobilization efforts, and offer providers another forum in which to collaborate and consult. Yet, despite their promise, little systematic empirical research has documented the content and characteristics of health blogs and bloggers. Virtually everything written about blogs to date has consisted of anecdotes and descriptions of individual blogs. Many articles focus on the use of blogs by health care professionals to chronicle their lives and practices. 8 – 23 Several articles focus on the use of blogs by providers and patients coping with and learning about particular diseases and conditions. 21 , 24 – 27 The potential role of blogging in health education, 28 – 37 research collaboration and dissemination, 6 , 38 and disaster planning 39 has been discussed as well. The few systematic empirical studies suffer from serious limitations, such as narrow focus (physicians, nurses, cancer, or mental health) or small sample size (47–271 blogs, bloggers, or blog readers). 40 – 44 We systematically cataloged the content and characteristics of the most influential health blogs and bloggers to provide a more thorough understanding of the health blogosphere than has been available to date. We aimed to identify the types of people who blog about health and health care, what elements and activities health blogs feature, what topics health bloggers write about, and from what perspectives health blogs are written.
