A coarse-graining of spin networks is expressed in terms of partial tracing, thus allowing to use tools of quantum information theory. This is illustrated by the analysis of a simple black hole model, where the logarithmic correction of the Bekenstein-Hawking entropy is shown to be equal to the total amount of correlations on the horizon. Finally other applications of entanglement to quantum gravity are briefly discussed.

RevTex, 5 pages. Proceedings of QG'05, Cala Gonone, 2005 Relations of the coarse-graining and partial tracing are clarified, and the references are updated