Dynamic Features of Social Tagging Vocabulary: Delicious, Flickr and YouTube

This article investigates the dynamic features of social tagging vocabularies in Delicious, Flickr and YouTube from 2003 to 2008. It analyzes the evolution of the usage of the most popular tags in each of these three social networks. We find that for different tagging systems, the dynamic features reflect different cognitive processes. At the macro level, the tag growth obeys power-law distribution for all three tagging systems with exponents lower than one. At the micro level, the tag growth of popular resources in all three tagging systems follows a similar power-law distribution. Moreover, we find that the exponents of tag growth varied in different evolving stages of popular individual resources.