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. Clicking on the tag's link will display a list of all the article abstracts associated with that keyword.
MALLET is an integrated collection of Java code useful for statistical natural language processing, document classification, clustering, information extraction, and other machine learning applications to text.
WIKINDX is a free bibliographic and quotations/notes management and article authoring system designed either for single use (on a variety of operating sytems) or multi-user collaborative use across the internet.
A. Aschenbrenner, M. Kuster, C. Ludwig, and T. Vitt. Digital Ecosystems and Technologies, 2009. DEST '09. 3rd IEEE International Conference on, page 745 -750. (June 2009)
S. Asur, and S. Hufnagel. Rapid System Prototyping, 1993. Shortening the Path from Specification to Prototype. Proceedings., Fourth International Workshop on, page 42 -56. (June 1993)