Comments from the link below, "Recognized a visio document from the email in the browser. (I�m not sure how this file format will be supported, if at all, but I found it interesting that it was recognized."
So wait, you're saying that someone saying a particular file extension was "recognized", means that the document can be displayed? Bit of a leap, isn't it?
This thread should be renamed [RUMOR]... (Edit: or, [Speculation] works too... )