中文：

奇虎360是中国知名的互联网安全公司，成立于2005年，总部位于北京。公司开发了一系列安全软件产品，如360安全卫士、360杀毒等，为用户提供全面的网络安全保障。那么，奇虎360什么时候上市的呢？

奇虎360于2011年7月18日在美国纳斯达克交易所上市。此次上市融资了近2亿美元，为公司的进一步发展提供了资金支持。作为中国互联网安全领域的领军企业，奇虎360的成功上市也引起了广泛的关注和热议。

上市后的奇虎360，借助资本市场的力量，不断拓展业务领域和提升技术水平。公司相继推出了360浏览器、360云服务等创新型产品，为用户提供更加全面的互联网服务。同时，奇虎360也加大了对研发的投入，不断推出新的安全技术和产品，以应对日益复杂的网络安全威胁。

总的来说，奇虎360的成功上市为其发展提供了新的机遇和动力。借助资本市场的力量，公司不断壮大和进步，成为了中国互联网安全领域的佼佼者。

英文：

Qihoo 360 is a well-known Internet security company in China, founded in 2005 and headquartered in Beijing. The company has developed a series of security software products such as 360 Security Guard and 360 Antivirus, providing users with comprehensive network security protection. So, when did Qihoo 360 go public?

On July 18, 2011, Qihoo 360 listed on the NASDAQ stock market in the United States. The listing raised nearly $200 million in funding, providing financial support for the company's further development. As a leading enterprise in China's Internet security field, Qihoo 360's successful listing has also attracted widespread attention and debate.

After listing, Qihoo 360 used the power of the capital market to continuously expand business areas and improve technological levels. The company launched innovative products such as 360 Browser and 360 Cloud Services, providing users with more comprehensive Internet services. At the same time, Qihoo 360 also increased its investment in research and development, continuously launching new security technologies and products to cope with increasingly complex network security threats.

Overall, Qihoo 360's successful listing provided new opportunities and impetus for its development. With the help of the power of the capital market, the company continued to grow and progress, becoming a leader in China's Internet security field.