This dataset is from a WBS case study that looks at some work done by Discovery Vitality on their Facebook page. Over the years, the Vitality research and development $($R&D$)$ department, in collaboration with the Vitality marketing team, had monitored the Vitality Facebook progress from a business perspective. Initially, the R&D team had only monitored the impact of the marketing content, but from $2010,$ Head of Strategic Initiatives had started to research other questions. One of these questions was whether different ways of phrasing an invitation to join the Facebook page would lead to differing response rates. She was also interested in whether participation in the Facebook page led to better health outcomes, this question is explored in a different case study.