Sex sells, as the saying goes - or does it? The pool of illicit videos featuring the rich and famous in assorted compromising positions seems to expand each week, and the celebrity-sex tape is now a global phenomenon. Among the more recent scandals garnering widespread attention is one involving Vietnamese television actress Hoang Thuy Linh, a virtual unknown outside her native land before a five-minute clip of the young woman getting intimate with her boyfriend surfaced on the internet. A lot more people have heard of her now, but it would be hard to argue the romp improved Hoang's job prospects. Vietnam remains a conservative place and pressure from indignant parents has forced the state broadcaster to pull the plug on the teenage soap opera that had defined her career. Some sex-tape stories in other countries have more beneficial endings. In fact, there's a pretty visible connection in Hollywood between unsanctioned pornography and a rise in celebrity fortunes. One obvious example is socialite Paris Hilton, who, thanks to the timely leak of a raunchy videotape just a week before her TV debut in reality show The Simple Life, saw the first couple of episodes attract a much higher than anticipated 13 million viewers. Whether the leak was deliberate or not remains unknown, but there must be a reason Hilton biographer Chas Newkey-Burden has called her a 'business genius'. Pamela Anderson had only a supporting role in Baywatch, but in 1998, not long after a clip of her frolicking on a yacht with then-husband Tommy Lee was widely distributed, she was made the star of her own show - VIP, a comedy-drama that cast her as a bodyguard/private detective. Titillating recordings are now seen as such an effective catapult to notoriety that D-list celebrities are practically queuing up to release them. In 2004, American professional wrestlers Joan Laurer, better known as Chyna, and Sean Waltman, or X-Pac, convinced an adult-film-industry heavyweight to market a homemade video of one of their trysts. While the pair haven't exactly become the toast of Tinseltown, the stunt did at least earn Laurer a place on The Surreal Life, a long-running series on music channel VH1. Any would-be idols hoping to pursue this fast track to fame should remember that for every Paris or Chyna there's a celebrity whose racier moments have met with indifference or outright revulsion. South Korean singer Baek Ji-young was an up-and-coming princess of pop in 2000 until a clip of a late-night encounter with a former manager surfaced on a porn site and started burning up hard drives nationwide. Her fourth album, released a year later, sold barely half as many copies as one that came out just before news of the tape broke. Men tend to fare worse than women when it comes to the returns on their sex-tape investment. Although his career has since enjoyed something of a recovery, actor Rob Lowe's prospects nose-dived 20 years ago after he recorded a sex session involving a girl who turned out to be underage. And co-starring in the Anderson video hasn't done much for Tommy Lee, who hasn't had a platinum-selling album since his days as a drummer for heavy metal band Motley Crue.