title: Pro-anorexia and pro-recovery photo sharing: a tale of two warring tribes.
abstract: BACKGROUND
  There is widespread use of the Internet to promote anorexia as a lifestyle choice. Pro-anorexia content can be harmful for people affected or at risk of having anorexia. That movement is actively engaged in sharing photos on social networks such as Flickr.
  
  
  OBJECTIVE
  To study the characteristics of the online communities engaged in disseminating content that encourages eating disorders (known as "pro-anorexia") and to investigate if the posting of such content is discouraged by the posting of recovery-oriented content.
  
  
  METHODS
  The extraction of pro-anorexia and pro-recovery photographs from the photo sharing site Flickr pertaining to 242,710 photos from 491 users and analyzing four separate social networks therein.
  
  
  RESULTS
  Pro-anorexia and pro-recovery communities interact to a much higher degree among themselves than what is expected from the distribution of contacts (only 59-72% of contacts but 74-83% of comments are made to members inside the community). Pro-recovery users employ similar words to those used by pro-anorexia users to describe their photographs, possibly in order to ensure that their content appears when pro-anorexia users search for images. Pro-anorexia users who are exposed to comments from the opposite camp are less likely to cease posting pro-anorexia photographs than those who do not receive such comments (46% versus 61%), and if they cease, they do so approximately three months later. Our observations show two highly active communities, where most interaction is within each community. However, the pro-recovery community takes steps to ensure that their content is visible to the pro-anorexia community, both by using textual descriptions of their photographs that are similar to those used by the pro-anorexia group and by commenting to pro-anorexia content. The latter activity is, however, counterproductive, as it entrenches pro-anorexia users in their stance.
  
  
  CONCLUSIONS
  Our results highlight the nature of pro-anorexia and pro-recovery photo sharing and accentuate the need for clinicians to be aware of such content and its effect on their patients. Our findings suggest that some currently used interventions are not useful in helping pro-anorexia users recover. Thus, future work should focus on new intervention methods, possibly tailored to individual characteristics.
authors.affiliation: Microsoft Research, Herzliya, Israel.
authors.forename: Elad
authors.initials: E
authors.lastname: Yom-Tov
authors.forename: Luis
authors.initials: L
authors.lastname: Fernandez-Luque
authors.forename: Ingmar
authors.initials: I
authors.lastname: Weber
authors.forename: Steven P
authors.initials: SP
authors.lastname: Crain
mesh_terms: D000855:Anorexia / Q000523:psychology* / Q000534:rehabilitation*; D006801:Humans; D020407:Internet