More than 25% of all visitors to websites in the US did so using IE7, making it the second most-used browser after IE6, according to WebSiteStory, a company that tracks these things.

We expect these numbers to continue to rise as we complete our final localized versions, scale up AU distribution, and with the consumer availability of Windows Vista on January 30, 2007, said IE group manager Tony Chor, on his corporate blog.

Microsoft made security improvements with IE7 over its predecessor, by eliminating some of the code that may have led to exploitable vulnerabilities. However, IE7 is still widely considered to contain security bugs and potential vulnerabilities.