One surprising problem that IE 7 betas have run into over recent months is that Web sites that were coded to work specifically with Internet Explorer weren't working with IE 7. The cause of this problem was that, since it's a new version of the browser, IE 7 has its own unique user agent string, which is how browsers identify themselves to Web sites (for the record, IE 7's string on Windows XP is Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)) The new string caused many sites to reject IE 7 as incompatible with IE-only Web sites. As the newer betas of IE 7 have increased in visibility this problem is now less common. And for those IE 7 beta testers still running into incompatible sites, there's a utility that can help you work around the problem.