An anonymous reader on .slashdot.org notes that Hotmail's full version doesn't work with Firefox 3. Users get the following message when they try to log in: You are temporarily on the classic version of Windows Live Hotmail due to an error encountered during login. Before trying again, please clear your cache and cookies. (Clearing cache and cookies doesn't fix it.) At least 8 other bug reports have been duped to this one. The fault apparently lies with the Hotmail site, not Mozilla — maintainer Dave Garrett assigned the bug to Tech Evangelism, explaining: "I'll... move this over to TE, as my guess is this [is] the site's fault (just bad user agent sniffing?)."
Microsoft needs to do a lot of testing.