In the light-speed world of information change I find myself trying to determine when a term first started to be used. In some cases I am trying to find the most appropriate current usage or spelling, while in other cases I am trying to determine whether a term or concept has recently morphed to another track. Google's "Ngram Viewer" may provide insight.
Recently Google introduced its "Books Ngram Viewer" to plot word usage from millions of books in Google's growing digital library. Journalist Robert Holt discusses Ngram Viewer in more detail in his 17 December 2010 Wall Street Article "New Google Database Puts Centuries of Cultural Trends in Reach of Linguists."
The Ngram Viewer is based on data derived from the use of Optical Character Recognition (OCR) interpreting millions of books that vary in quality and English usage. For example, the long, medial or descending "s" appears as an "f." "Congrefs" (in Wikipedia article on the United States Bill of Rights) shows usage of this character. As a result, word traces from earlier periods may be less accurate (Google discusses Ngram issues here).
This shouldn't cause problems for me studying more recent terms, except for instances of time-traveling software engineers (i.e.possible explanation of why the phrase "Internet" occurs before 1950).