You type in one or more words or phrases, comma separated, case sensitive, and it returns a graph of the usage of the words or phrases over time.

I had some fun with it, and perhaps you will too. Try "deficit disorder" or "post-traumatic stress" to see, roughly, when each entered the general vocabulary.

Here.

AmProf,
     You're right; it is fun and also instructive. I tried web log and, as expected, a recent origin is indicated. Checking blog, however, shows the word in use since the 18-hundreds. I wonder what it meant back then?
Seán

It's awesome.....sooo I tried awesome. Most amusing.

And diss? Wonder what it meant in 1820?