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The differences betwen IE6 and IE7 are like night and day! Problem with telling people not to use IE is that it would never work. "Zillions" of "general users" Worldwide are continuing to purchase Windows machines and most of those setups alresdy have WinXP Pro SP3 or Winvista SP1 installed, to include IE7. Besides, unless you have a technical site your own stats will more than likely show that most of your visitors are IE users due to what I just mentioned. In our case we're getting well over 80% of our traffic from IE users.
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It wasn't too long ago (little over 2 years) that I was still telling everyone and the world to dump IE in lieu of FF and a couple of years before that in lieu of Netscape, but I have to admit that ever since IE7 came out, I'm pretty darn pleased with it. I bet if MS offered a couple of dozen free IE skins it would cause bunch of people (non-techies) to switch back from FF to IE altogether. As far as regular usrs go though, I don't even know why anyone would still be using IE6 since IE7 has been out since September of 2006, two and a half years ago. High time to get updated .... :)
(that's what I'd be telling someone who can't sign up due to IE6 being used)
It's easier than telling a non-techie or a new computer user to start downloading and installing on their own ...
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Greetings from Germany