Great Internet entrepreneur with small problem in his blog

Just using this post to upload a screen shot of a great Internet entrepreneur who have a blog, but in which I spotted a small problem. See screen shot below:



See that gray box, don't know what it is, jutting out beyond the boundary of the blog? I suspect if that blog is viewed with Internet Explorer 6, maybe even IE7, the sidebar may be pushed to bottom of the page. Wonder if I should take time to view page source to try to diagnose the problem.