Hotmail Live Password Changes?

Okay, so I have an account on the Hotmail/Live service and today, without explination or warning, a change has occured that is a bit unsettling.  Most especially in the wake of 450,000+ users being hacked over at the “other” large email provider we will not discuss.

I attempted to log in to the account today only to be greeted by the following:
“Microsoft account passwords can contain up to 16 characters. If you’ve been using a password that has more than 16 characters, enter the first 16.”

So a password I was using that is over 16 characters (and I typically use passwords well over this amount of characters) is suddenly not a “supported” password?

Now why would you go do that?