Presentation slides associated with the paper "Enhancing Social Tagging with a Knowledge Organization System" written by Koraljka Golub, Jim Moon, Douglas Tudhope and Marianne Lykke Nielsen, accepted for the IFLA Satellite Meeting, Emerging Trends in Technology: Libraries Between Web 2.0, Semantic Web and Search, Florence, 19-20 August 2009. Much of the content of the slides is taken from previous presentations given by Koraljka Golub of UKOLN and Brian Matthews of STFC