I didn't notice this issue for a long time (albeit I am a long term hotmail user, but I seldom use it for 'serious' purpose (like job, getting bills etc). Of late, I tried hotmail for some of my service billings (like broadband, bank etc.)
Quite interestingly, I am NOT able to open any PDF attachment received via hotmail account. I tried in Firefox 3.6 and I.E 7.I have to forward to my gmail account to open it.
Incredulously, I googled and yep that is expected. You cannot open PDF attachment in hotmail for security purpose! Guyz, this is too bad , may be okay in technical perspective but not in user's perspective, across the globe I strongly believe bills and other important documents are coming in PDF format (with or without encryption) and if those cannot be opened from hotmail....