I found a great list on the blog/news section for the ocPortal CMS, 10 IE compatibility problems that you might not have realized. While the post is related to ocPortal, the Internet Explorer compatibility issues likely will apply to any CMS viewed by the browser.
Over the year's ocProducts has maintained a private list of issues in different web browsers, and if there's one thing that is consistent it is that Internet Explorer has the majority of the problems. Sometimes they are bugs, but as you'll see from this list sometimes other browsers just do things better. I am writing this blog post not to bash Microsoft, but hopefully to provide some useful information to other web developers. Thankfully IE8 fixed a ton of problems, and I can't wait until we can ditch IE6 and IE7, but unfortunately this will inevitably be years away; never-the-less, as far as I am aware every problem here applies to IE8 as well as older versions.
I wouldn't be surprised if IE8 fixes some of the incompatibility issues that the author lists. I've been using IE8 at both home and work and have found the browser to be an improvement over IE6 and IE7. Nevertheless, I still prefer Firefox over Internet Explorer.
Now, the following rant isn't directed toward ocPortal but something that has hit a sore spot with me.
The author talks about the need to keeping sites compatible with IE6 and I think this is definitely up for debate. One of the biggest issues with using IE6 in my opinion is that it is an insecure browser. When Microsoft itself recommends that you upgrade from IE6 to IE7 or IE8 due to security concern, I think it's lousy for site owners to promote IE6 compatibility through their sites. There comes a time when you can't keep blaming Microsoft for Internet security issues but the users that continue to use insecure software as well as the companies that allow their users to connect to their sites with insecure software.
A couple years ago someone started a goPHP5 campaign to promote getting hosting companies and CMS projects off of PHP4 and onto PHP5. Perhaps it's time to start a byeIE6 campaign to get people seriously off this outdated and insecure browser. Either way, it's time for Internet users to move on...