From the New Economist blog, I learned about this interesting website, the State of the Union, at which you can read the text of every presidential State of the Union address, from G.W. in 1790 to G.W.B. in 2006.
The horizontal axis is simply alphabetical. The vertical axis displays the word’s significance, determined by comparing how frequently the word occurs in the document to how frequently it appears throughout the entire body of SOTU addresses
Fans of the idea that our society is getting progressively dumber will be happy to see that SOTU addresses have been much shorter since 1900, and their their Flesch-Kincaid reading grade level sloping gently downward since 1790. A more positive spin on that data might be that it reflects the increasingly democratic nature of our politics, and the need of politicians to speak more common language.
The example displayed above is from George W. Bush's 2002 SOTU. Our current president is the only one to feature the word 'applause' prominently in any SOTU. In fact, it's prominent in every one of his speeches. Apparently the transcripts of Bush's speeches are the only ones to inlcude the notation "(Applause.)" I'm tempted to ascribe this to the Bush administration's reflexive need for displays of fealty, but it could easily be an artifact of the source of the texts.