I build websites, and even when we supported Internet explorer 6, my company wouldn't allow us to display a message like this. Anyone who ever developed a website for IE6 would know that if it were ever appropriate to display such a message, it was for IE6. It was atrocious beyond words. They ignored most of the standards and the browser was also just a security nightmare, yet still just on principle alone the idea was always shot down.
"Why spend thousands of dollars on paying someone to fix it when we can pay them hundreds to spend an hour writing a dialog box?" - Some storefront owner