OMG! So Interesting!!

Encouraged by a new style guide to use exclamation points liberally in e-mail correspondence, an article in Slate today points out their original use:

A relatively recent addition to the punctuation clan, it first appeared in print around 1400 and was known until 1700 as a "mark of admiration," though admiration in this case meant something like "wonderment" (of a religious variety). Some scholars believe it derives from the Latin Io (meaning joy). Io, the theory goes, might have been rendered with its second letter under the first, thus producing an exclamation mark.

and some of the sad effects of the medium itself:

For centuries, the act of writing mandated a tremendous exertion of labor, so that scribes committed to the page only texts of supreme import. (Imagine a team of tonsured monks toiling for decades on an illuminated manuscript that read, "WTF … c u l8r?") For centuries, that which was written had to deserve to be written. Today's technology, however, allows us to transmit doodles of thought (e.g. "Running 10 mins late") we never would have deemed worthy of print. It's not that we know we aren't writing well—and so tack on some exclamations!!!—it's that we know what we're saying doesn't deserve to be written at all.