The original infochimps blog post is at http://blog.infochimps.org/2009/11/11/twitter-census-publish...

Seems there is very interesting info out there:

* The packaged data was contains almost the entire history of Twitter: 35 million users, one billion relationships, and half a billion Tweets, reaching back to March 2006.

* the first dataset has # Hashtags, links and smiley emoticons used across Twitter on an hour by hour basis.

* the second dataset contains @ messages, RT and favorites and who they came from - 1 Billion relations making what the company calls a "conversation metric."