The Tweetsphere is already quite crowded with aggregate and visual interfaces (think Twitter Blocks, Tweet Stats, Tweet Volume, Twitter Meter, Tweetpad, Twitter Counter, and many more), but this one seems to stand out in terms of its interactive and real-time tracking features, maybe conceptually similar to those found at Digg Labs.
PepsiCo SXSW Zeitgeist [pepsicozeitgeist.com] is an online tweet visualizer, designed by Slash7, that takes the pulse of SXSW 2009, a five day symposium celebrating the best minds and the brightest personalities of emerging technology.
Tweets relevant to the festival are ordered by category (e.g. arriving, drinking, registering, eating, connecting or partying), analyzed for popular keywords, geolocated on a map of Austin, or filtered by highlighting quotations within tweet messages.
Interesting panels at SXSW include: Tangible Interactions in Urban Spaces, Designing the Future of The New York Times, Edupunk: Open Source Education, My Car Is Talking But What's it Saying?, Minority Report is Real, The Future of Visual Storytelling is Interactive -- Or Is It? and Get Me Rewrite! Developing APIs and the Changing Face of News.
Any person attending SXSW wishing to guest blog about these topics is more than welcome at infosthetics.com!