This is a Background document to 'A Social Framework for Big Data', which proposes an agenda that understands how social composition and social effects are related and proposes that giving Big Data a ‘social intelligence’ requires acting with an ethic of care. The Background provides a discussion of some conceptual issues and debates related to this agenda. Both documents along with a working paper, 'Socialising Big Data: from concept to practice' are the product of an ESRC funded project, Socialising Big Data, led by Evelyn Ruppert (2013-14).