By CONNIE KOENENN - Copyright 1997 Los Angeles Times (who copied it it from a book by Gareth Branwyn titled Jargon Watch.) 404: Someone who's clueless. From the World Wide Web error message "404 Not Found," meaning that the requested document could not be located. "Don't bother asking him ... he's 404, man." Geekosphere: The area surrounding one's computer, where little trinkets, personal mementos, toys and monitor pets are displayed. The place where computer geeks can show their "colors." In the Plastic Closet: Said about someone who refuses to admit to having cosmetic surgery. I-Way: Short form of information superhighway. Mouse Potato: The online, wired generation's answer to the couch potato. Ohnosecond: That minuscule fraction of time in which you realize that you've just made a big mistake. Open Collar Workers: People who work at home or telecommute. Siliwood: Short for "Silicon Hollywood," the coming converge of movies, interactive television and computer. Starter Marriages: Short-lived first marriages that end in divorce with no kids, no property and no regrets. Tract Mansions: Large, expensive homes built in tractlike developments by the nouveau riche. Xerox Subsidy: Euphemism for swiping free photocopies at the workplace. Yuppie Food Coupons: The $20 bills spewed out of ATMs everywhere. Often used when trying to split the bill after a meal: "We each owe $8, but all anybody's got is yuppie food coupons.