A recent Internet survey shows daily user numbers of the 360 Safe free anti-virus software has surged to nearly 60 million, up from 470 thousand a year ago. This makes 360 Safe number one in China's anti-virus market. And it's the first time a free program beats the paid ones.

KingSoft is a veteran in Internet security. For years, it's stuck to charging for its anti-virus software. And recently, it launched two versions.

He Yandan, Product supervisor, said, Kingsoft Internet Security, said, "There are hundreds of millions of Internet users in China, which is a huge number. They know clearly about online threats, and they're very good when it comes to do-it-yourself. So we try to provide more options for them to make their own combinations of products."

Most anti-virus software, both domestic and foreign, still requires a fee. He Yandan says it has to do with quality.

He Yandan, Product Supervisor, Kingsoft Internet Security, said, "We all know that anti-virus software requires a lot of money. Anti-virus software companies need lots of servers and professional staff, which are very high cost. Without any income, it's hard to imagine what products and services that company could provide."

But 360 Safe, which has always provided free anti-virus software, disagrees.

Staff of 360 Safe, said, "In fact, it's just the opposite. The quality pressure is quite small for paid anti-virus software. When Internet users buy the software for 300 yuan, they aren't likely to give it up even if the software is not very satisfactory, because of the 300 yuan. On the contrary for our free anti-virus software, it's easy to install. But when users get dissatisfied, they will uninstall it immediately."