Three links today, all on the same subject: the semicolon.
First, here's me writing about them three years ago.
Second, here's an article from Monday's New York Times.
Third, here's something rather strange, but pretty accurate.
I know a chap who had a gut operation that left him with a semicolon.
And here's a graph of the frequency of semicolons in English from 1500 to the present.