Web2.0Slides is a self-running slide show of over 1,400 of the best Web2.0 sites. It's categorized by tags and sorted alphabetically. What's cool about it? You can click on any site in the left-hand column to pause the slide show and surf around. When
New Ajax social bookmark URL(you can see with what tags one have bookmarked you) and tag search. Says it will be adding more social bookmarking query services almost daily.
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.
B. Krause, R. Jäschke, A. Hotho, и G. Stumme. HT '08: Proceedings of the Nineteenth ACM Conference on Hypertext and Hypermedia, стр. 157-166. New York, NY, USA, ACM, (2008)