There isn't a single day where I hear about a new system, or an academic project who is utilizing graphs for getting additional insights out of the data. Today I heard about an interesting study of taste from Prof. Alon Ben-Ari, Director Medical Informatics Fellowship Program, University of Washington - VA Medical Center:
Ahn, Yong-Yeol, Sebastian E. Ahnert, James P. Bagrow, and Albert-László Barabási. "Flavor network and the principles of food pairing." Scientific reports 1 (2011).
This paper analyses connections between recipe components using graphs. For each pair of ingredients that appear in a recipe together a graph edge is created.