There is a really interesting new study available at http://arstechnica.com/news.ars/post/20060803-7417.html regarding the use of computers to track phrases or packets of words in the Congressional Record. The researchers describe in their report their method for assigning computers certain words to track and then measuring the use of those phrases in comparison to other phrases. Essentially, what the scientists have achieved is a means of finding out what members of Congress are talking about and how those topics change over time. For example, "Judicial nominations" is the most used phrase, while "abortion" has been on the decline. The findings also offer interesting insights into the perspectives of members of Congress. According to the authors "[t]he most interesting meta-cluster is the substantively odd “regional” grouping of energy, environment, agriculture, and trade. Exploration of the language used here shows that these are topics that divide rural and or Western senator from the rest – distributive politics at a different level of aggregation."
Note that the overall report is very technical -- the most interesting findings for practitioners start around section 4.