Normally, I would endeavor to research the tools I present a little more before sharing, but I've been having so much fun exploring this list that I had to present it (that, and I'm almost out of minutes left in the day). KDNuggets, a data mining & knowledge dicsovery guide website has a fantastic list of Information Retrieval tools that deserve to be played with.

I've personally only experimented with a few, namely textalyser and an offering from Megaputer called textanalyst (guess I've got a one-track mind). I recently made a post on SEOChat saying that the more I learn, the more I find myself knowing less. This area of research is an excellent example of that lack of knowledge. I'll let you know if and when I'm able to make sense of these tools.