  Background: Social media public health campaigns have the advantage of
tailored messaging at low cost and large reach, but little is known about what
would determine their feasibility as tools for inducing attitude and behavior
change.
  Objective: The aim of this study was to test the feasibility of designing,
implementing, and evaluating a social media-enabled intervention for skin
cancer prevention.
  Conclusions: Social media-disseminated public health messages reached more
than 23% of the Northern Ireland population. A Web-based survey suggested that
the campaign might have contributed to improved knowledge and attitudes toward
skin cancer among the target population. Findings suggested that shocking and
humorous messages generated greatest impressions and engagement, but
information-based messages were likely to be shared most. The extent of
behavioral change as a result of the campaign remains to be explored, however,
the change of attitudes and knowledge is promising. Social media is an
inexpensive, effective method for delivering public health messages. However,
existing and traditional process evaluation methods may not be suitable for
social media.
