Neat! I did some similar analysis of conducting topic modeling around tweets during the Boston Marathon bombing a couple of years back. It was pretty cool to see how topics were neatly ordered over time.

http://blog.dc.esri.com/2013/04/18/the-evolution-of-discussi...

404. Correct URL: http://blog.dominodatalab.com/topic-modeling-in-sept-11-news...