Google Trends is a nice tool to reconstruct how some search terms have been used over time. In the picture below I tried the name of two learning technologies paradigm which do not mean anything per se. Usually around these buzz words there are very different ideas and a great deal of interest. The graph shows how people are less and less using the word e-learning and how the word mobile learning is barely used since the last quarter of 2004. Interesting.
With Google Trends, you can compare the world’s interest in your favorite topics. Enter up to five topics and see how often they’ve been searched for on Google over time. Google Trends also displays how frequently your topics have appeared in Google News stories, and which geographic regions have searched for them most often.