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, or as we know it - :-). 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., carries a $500 cash prize. Language experts say the smiley face and other emotional icons, known as emoticons, have given people a concise way in e-mail and other electronic messages of expressing sentiments that otherwise would be difficult to detect. Fahlman posted the emoticon in a message to an online electronic bulletin board at 11:44 a.m. on Sept. 19, 1982, during a discussion about the limits of online humor and how to denote comments meant to be taken lightly. "I propose the following character sequence for joke markers: :-)," wrote Fahlman. "Read it sideways."