The formal study of knowledge goes back to Hintikka in the 60's and has become a veritable industry in the last thirty years or so. However, its importance in the running of society has been less studied. We will give some formal and informal examples of the way in which knowledge and knowledge transfer enter social algorithms. We describe some of the older work of Aumann, Geanakoplos and Polemarchakis, Parikh and Krasucki as well as more recent work of ourselves with Pacuit and Cogan.