A new survey of online flirting by dating website Badoo.com has found that the best Internet chat-up line for men to use is: "You have beautiful lips." "We have found the magic wand of flirting," said Badoo Director of Marketing Lloyd Price.

The site, which boasts 87 million registered users worldwide, analyzed the success rates of opening lines from nearly 200,000 online flirtations in 11 languages over the course of one month to come up with a "Compliment Success Index." Site users were invited to use one of 12 different chat-up lines.

Each complimented an aspect of a woman's body or appearance. Researchers measured the success rate of each line in two ways: First, their success at prompting any response at all; second, their success at launching a longer conversation - one going back and forth at least four times. Complimenting a woman's lips was the most successful overall, but other lines worked best in particular countries.

American, French, Italian or Brazilian women were more responsive to "You dress beautifully." Brits preferred praise for their legs, Spaniards responded to compliments about their hair, while Germans and Canadians preferred skin praise. Dutch and Portuguese women liked: "You have beautiful ears." Jo Hemmings, a British behavioral psychologist said women responded best to compliments about their lips because it's a bold approach that seems more personal.