Creating a fake boyfriend to make your ex jealous used to be a complicated matter (see The Wedding Date), but now, all it takes is a laptop and a little free time. After Tatum, a 28-year-old New Yorker, broke up with her BF, she started seeing posts on his MySpace page from women she'd never met (but who looked kind of slutty). So, she found a photo of a handsome, shaggy punk bassist from Portland and created a profile for him (a surfing nonprofit owner named Kai, with degrees in art history and business ethics). Then she started dropping flirty posts on both pages full of references to "last night." Even after Tatum got what she wanted, a deeply satisfying e-mail — "So, he's into surfing, huh?" — from her ex-boyfriend, she says she kept Kai around: "It's kind of like having a pet."