Situated learning is one of many different learning theories. In brief summary, it says that much learning is quite specific to the situation (activity, context, culture, environment) in which it occurs. See http://www.learning-theories.com/situated-learning-theory-lave.html. Quoting from http://tip.psychology.org/lave.html:
Other researchers have further developed the theory of situated learning. Brown, Collins & Duguid (1989) emphasize the idea of cognitive apprenticeship: "Cognitive apprenticeship supports learning in a domain by enabling students to acquire, develop and use cognitive tools in authentic domain activity. Learning, both outside and inside school, advances through collaborative social interaction and the social construction of knowledge." Brown et al. also emphasize the need for a new epistemology for learning -- one that emphasizes active perception over concepts and representation. Suchman (1988) explores the situated learning framework in the context of artificial intelligence.