什么样的笑最令人难忘？蒙娜丽莎式的神秘莫测、意蕴无穷，还是网络笑脸(smiley face)的纯粹简约与无处不在？古典也好，时尚也好，无不来自灵感的闪现。

　　All over the country these days, electronic mail messages are concluding with this odd little punctuation sequence :-) or one of its many variants, like :-( .<注1>

　　These are smileys, so-called because when you tilt your head to the left they look like little faces with a colon for eyes and a hyphen for a nose.<注2> Thus when a message ends :-) it means must kidding. If it ends :-( it means I'm depressed. If it ends 7:^] it means I resemble Ronald Reagan.?

　　It was 20 years ago that Scott Fahlman taught the Net how to smile. The Carnegie Mellon computer scientist has devoted his professional life to artificial intelligence,<注3> the practice of teaching computers how to think like humans, but the bearded scientist is perhaps best known for a flash of inspiration that helped to define Internet culture.<注4>

　　By the early 1980's, the Computer Science community at Carnegie Mellon was making heavy use of online bulletin boards<注5> or bboards A good many of the posts were humorous. The problem was that if someone made a sarcastic remark<注6>, a few readers would fail to get the joke. This problem caused some people to suggest (only half seriously) that maybe it would be a good idea to explicitly mark posts that were not to be taken seriously.<注7>After all, when using text-based online communication, we lack the body language or tone-of-voice cues that convey this information when we talk in person or on the phone.<注8>

　　So on Sept. 19, 1982, Fahlman typed :-) in an online message. I had no idea I was starting something that would soon pollute all the world's communications channels, he later wrote. The smiley face has since become a staple<注9> of online communication, allowing 12-year-old girls and corporate lawyers alike to punctuate their messages with a quick symbol that says, Hey, I'm only joking.?

　　This convention caught on quickly around Carnegie Mellon,<注10> and soon spread to other universities and research labs via the primitive computer networks of the day. In the two decades since, the smiling icons have taken the e-world by storm.<注11> Now called emoticons, short for emotive icons,<注12> Fahlman's original sideways smiley face sparked the creation of thousands of variations.

　　Yahoo, Microsoft and America Online all incorporate<注13> emoticonssintostheir instant-messaging systems, while telecom firms, jewelry makers and online retailers have filed trademark applications for<注14> products and slogans that incorporate Fahlman's smiley face.

　　But Fahlman has never seen a dime from his creation. If it cost people a nickel<注15> to use it, nobody would have used it. This is my little gift to the world, for better or worse, he said.