Occurrences of "guy" vs "chap" in books over the last 200 years - http://ngrams.googlelabs.com/graph...
Another fun one: [the morrow] vs [tomorrow] http://ngrams.googlelabs.com/graph... - Simon
Email sure was popular in the 1800s: http://ngrams.googlelabs.com/graph... - Amit Patel
Oh! - Amit Patel