TagCloud is an automated Folksonomy tool. Essentially, TagCloud searches any number of RSS feeds you specify, extracts keywords from the content and lists them according to prevalence within the RSS feeds.
Y. Hassan-Montero, and V. Herrero-Solana. Proceedings of Multidisciplinary Information Sciences and Technologies, InSciT2006, Merida, Spain, (25--28 October 2006)