Google has a new tool in which you can search the books that Google has digitized for a keyword and get statistics from as far back as the 16th century. The Google Book Ngram Viewer gives you data you can use to track the popularity of ...just about anything. For example, Geeks Are Sexy looked as terms like "geek", "computer geek", and "computer hacker" to ascertain that geeks are indeed, gaining in popularity. Link