Last week, Sarah Killen had three Twitter followers. This week, she has 20,000 - as well as a new iMac computer and offers to help pay for a dress and drinks for her wedding. Conan O'Brien decided last week to pick Killen as the only person he would follow on Twitter, turning the 19-year-old's life upside down. “I've decided to follow someone at random,” O'Brien's posting read at 3:55 P.M. on Friday. “She likes peanut butter and gummy dinosaurs. Sarah Killen, your life is about to change.” Boy, did it ever. Immediately after O'Brien started following her, Killen - whose Twitter handle is “LovelyButton” - picked up followers at a rate of 150 per minute. Then came the calls: Family, friends (actual and long-lost) and interview requests from Web sites, TV shows and radio stations. The exposure has resulted in a brand-new iMac, which was bought for them by a Florida businessman. A New York designer is donating a wedding dress.
