The web is rapidly becoming both more open and more social through the provision of technologies that make it easier for end users to access resources and join in social networks. Social networks have pioneered online communities, allowing users to contribute to collective knowledge by tagging online resources. Tagging behavior increased dramatically between 2005 and 2007. This paper reports on an investigation of social tagging using data gathered from Delicious, Flickr and YouTube for the years 2005, 2006 and 2007. Preliminary findings indicate both that it is possible to profile a social network through the analysis of tagging data and that Delicious is a more representative venue for analyzing the social tagging behavior of users than either Flickr or YouTube.