I'm sure you're all aware of the WMF vulnerability and all the hoohaw surrounding it as a potential backdoor implanted by Microsoft. Mark, in his latest post (as of this posting) gives a wonderful analysis as to why he believes it's not a backdoor by Microsoft. What I find most interesting about this post, however, is the inside look given by him into the vulnerability itself; most of us simply download the patch by Microsoft for the 'bug' and call it a day - but it's interesting to look deep into why the vulnerability existed in the first place and how some 'flaws' may actually be, originally, simply a feature.