Someone asked my why the "K" is used to indicate a strikeout, why not "SO".
I've just always kept score that way and never wondered about the history of it.
A very knowledgeable baseball friend says it is because K is the last letter in "strike" that could be used (e=error).
I have posted this to the SABR discussion list as well, but am wondering if AN knows (or what kind of stories AN might suggest. :))