RSS.
RSS Readers. Mapping the Network. Webpages as graphs - an HTML DOM Visualizer Applet. Twitter Friends Network Browser. Concept Tracking. Trendistic - see trends in twitter. BlogPulse.
Word Clouds. Popular Tags on Flickr. Twitscoop - Stay on top of twitter! - Search twitter, twitter cl. TagCrowd - make your own tag cloud from any text. Eye Candy. Tag Galaxy.