Hi there Todd,
So IE6 ended up being one of the worst browsers ever shipped: http://en.wikipedia.org/wiki/Internet_Explorer_6
It was terribly buggy, and software patches didn't help much. Here you can see the percentage of users worldwide who use IE6: http://www.ie6countdown.com/. In North America, it's less than 1%.
IE7 was better, but it was replaced in 2009 - our recommendation is to use the latest version of all browsers as we don't actively support degenerated browser versions. Since IE9 is out, we still are supporting IE8.
Our recommended browsers are Chrome and Firefox, but everything should also work well in the lastest versions of IE and other browsers.