Ping失败但http链接正常工作

In one of the system (Windows), if I ping to a particular public forum site, [lets say testsite.com here], then I get a request timed out message. However, if I just put that site address in the browser (used IE6, but its not specific) with https://, then the link works fine and the browser goes to the web page. What is it that the browser doing differently ?In one of the system (Windows), if I ping to a