Emile Durkheim - Social Facts - Material

Durkheim describes a social fact as the social structures and cultural norms that are coercive and external to the individual.  A material social fact is directly observable.
Here is an example of a material social fact according to Durkheim.  This is the terms and conditions, rights and responsibilities, policies, and standards of the online community Facebook.  These are legal codes.  Facebook's legal codes fall under Durkheim's material social facts because they are directly observable as well as coercive to the user as well as external to.