I love the look of the site! And kudos for using Haskell + Raphaeljs. It's a great example use-case for data mining Twitter. There are so many interesting data-mining mashup possibilities on Twitter that I've been disappointed by the lack of creative imagination shown in the various Twitter-based web apps aggregating and interpreting trends via Twitter.

However, I do wonder if it would be easy to spam Twitter and thereby ruin its usefulness for real-time data mining. If Twitter can be used to accurately track trends, as soon as everyone knows trends are being created based on Twitter, then they can manipulate it, similar to pump-and-dump spam schemes we've seen on various financial news boards, like Yahoo, Motley Fool etc.