I have taken the remarks made by both Clinton and Obama after the Super Tuesday results were in and constructed a Document Cloud Comparison. A few static images are shown below to give you a flavour but the real fun comes with exploring the interactive application.
Most Common Words (static image)
This first image shows part of the list of most common words for both speeches. Clinton mentions 'America' most frequently, Obama the word 'can'. Clinton uses the terms 'god' , 'auto', 'veteran', and 'economy' which aren't mentioned at all by Obama. Interestingly, Obama's top unique words are 'time' and 'change'.
'Hope' Associations and References (static image)
The references to the word 'hope' clearly show Obama's use of repetition and rhythm. This is shown again in his use of the words 'time' and 'change' as shown below.
'Time' & 'Change' Associations and References (static image)
The last reference to 'change' caught my eye - We are the change that we seek. It's the declarative form of a famous quote by Gandhi - You must be the change you want to see in the world.
It's much more interesting to try it out yourself. Click on 'more' to give it a try. The application is written in Java so you will have to wait a few seconds for it to start up.
Update: There is a new cloud comparison available for Obama and McCain remarks made after the Potomac Primaries.
The interactive application: