The coolest new thing to dick around on the internet to waste you time? Google ngrams.
It searches through all books on Google books, going back into the 1800s. Somewhere I read that this data set accounts for 5% of all books ever published, but I can't find where I read that, so set your belief levels accordingly.
Anyway, the ngram program allows you to search for how often different terms were used throughout whatever period you choose. So, in theory, you could use it to look at changing social norms over time, or the historical varieties of the English language.
Or you could use it to compare stupid things and giggle at the results. Either one is a totally legit use. Here's some awesome charts to improve your life:
Which do we write about more often, food or sex?
Do we write more about dudes or chicks?
What about communism versus socialism?
And, of course, when have we written more about punches, kicks, and ninja chops?