Although Swivel is one of my favourite sites at the moment (currently being overwhelmed by the Economist's daily chart news story), Many Eyes from IBM supplies some fantastic options for analysing text content. Unfortunately it does not yet offer embedding.
Have a look at the two pages I created analysing the text of Gordon's Speech:
First a normal tag cloud
Secondly a text analysis that shows the way certain words were used.
Quite useful way to get to the heart of a long speech. Could be useful for a presentation - turning a long argument into bite sized slides?