That happens due to a fatal bug with Internet Explorer. In your profile information in the left hand column of the page, It seems like there are several opening [ b ] BB code tags, but no closing [/ b ] BB code tags. This creates an error in the code that allows Web browsers to show the page on screen, and Internet Explorer is especially vulnerable for some reason. Firefox works just fine, in fact if I remember correctly Internet Explorer 7 works fine and it's Internet Explorer 6 that fails. All you need to do is edit your profile and make sure there is a [/ b ] for every opening [ b ]. I've also found this happening with the [ i ] BB code tag, where there is no closing [/ i ] tag.
I think we're going to start checking all text we add to the site for properly written BB code so Internet Explorer doesn't have this problem.