Although Internet Explorer 7 and the newly release Internet Explorer 8 have made progress in replacing the infamous Internet Explorer 6, there are still about 30% of users who still use it globally, and depending on your audience, that number could even be larger.
84% of DebonStudio.com visitors are using Internet Explorer, with roughly half of them being IE6. So 42% of the total visits are done using Internet Explorer 6. Compare this with the W3C School website, where almost 50% of visitors are using Firefox (IE6 users amount to only 15%).
A word about IE5.5 and earlier versions
I don’t worry too much anymore about IE5.5 and earlier versions. They are now representing such a tiny share of the browsers market that they can be safely ignored. But if you really, really, really want to accommodate these browsers, this page goes through the IE5.5 and earlier browsers bugs.