For a long time we have maintained that Mozilla and Opera are simply better browsers than IE. Now there are persistent security flaws in IE that hackers are regularly taking advantage of and pose threats to users even behind firewalls. Not having updated IE for 3 years has really come home to roost. And developers, not having having a “stick-with-W3C -standards” toggle switch (like that available from Adobe and Macromedia in their web development tools) in Microsoft development tools. The result is that developers targetting IE have fallen victim to using proprietary extensions which make their sites fray at the edge or even completely break up when broadly recommended defense measures (turn off Activex and Active scripting) are employed. Developers and their clients pay for overextending IE. This is partially due to their own deliberate programming and partly because Redmond uses ASP, Front Page, Visual Studio, Office Development Kit and other developer tools to generate proprietary but vulnerable code for exclusive use in IE.
But Mozilla and Opera often negotiate these same IE compromised sites with less ill effects and certainly less vulnerabilities. IT is now into security overtime and if you havent switched browsers dont wait for Longhorn. Mozilla and Opera are already clearly better browsers and are on track to provide some joint (see WHATWG) and individual breakthrough upgrades. The time to switch is NOW!