I am in love with Google Labs’ ngram viewer. If you haven’t played with this tool yet, you really should. The process is very simple – enter a word or phrase and see how our use of it has changed over time.
Here’s what I got when I entered the word “slavery.” 
Look at that peak in the 1860s. I guess I could have predicted that, but I wouldn’t have expected the massive vastness of the peak. (Perhaps this can help disspell the “states’ rights” myth about The Civl War?) Then, there’s another peak in the 1970s. Interesting, for sure.
I love how this shows us what our cultural conversations are. I also love how it shows the strength of words – how the both reflect and shape our culture. Such powerful data.
Take a look at this great TED video about the ngram process. Enjoy the humor and the science, and then go play. I may do this all day.
What words or phrases did you search? What did you find in those searches?