PITTSBURGH (AP) - It was a serious contribution to the electronic lexicon. :-) Twenty-five years ago, Carnegie Mellon University professor Scott E. Fahlman says, he was the first to use three keystrokes - a colon followed by a hyphen and a parenthesis - as a horizontal "smiley face" in a computer message. To mark the anniversary Wednesday, Fahlman and his colleagues are starting an annual student contest for innovation in technology-assisted, person-to-person communication. The Smiley Award, sponsored by Yahoo Inc. (YHOO) (YHOO), carries a $500 cash prize. Language experts say the smiley face and other emotional icons, known as emoticons,...