Questionnaires were distributed as e-mail attachments to personal contacts, and to members of the public on the social networking sites Twitter and Facebook. Other respondents werecollected by snowballing on the basis of the original contact group.Although access was a major driver in the sampling approach, thisconvenience sampling approach was also beneficial in building asample in which respondents all had the shared characteristic ofusing a mobile phone (Riley, Wood, Clark, Wilkie, & Szivas, 2000).Hair, Bush, and Ortinau (2006) suggest that self-selected samplingis suitable for exploratory research when prior knowledge of thepopulation’s characteristics is not sufficiently present.