Windows XP allows you to set Hotmail as the e-mail button at the top of the start menu by going into the taskbar properties. Does that also change the mailto links somehow? And is this being done in a standard way, or (the likely answer) a MS proprietary and undocumented way?
HKEY_CLASSES_ROOT\mailto\shell\open\command
Nope. Setting e-mail to Hotmail still kept Outlook as my mailto program, at least on my XP 64 box at work. And of course, clicking on the Hotmail button opened in IE, even though Firefox is set as the default browser on that machine and IE is turned off by the court mandated "Set Program Access and Defaults".
So to go back to:
Yup, just a sense of academic curiosity, wondering aloud why it's so tough to to make a web-based mail service launch from a mailto link.
It looks like MS doesn't have a way to do this built in, even when they own both the web mail service and the OS. It's odd that selecting Hotmail goes to a web site instead of trying to configure Outlook Express for your hotmail account. With .Mac, all you have to do is plug in your username and password at machine setup time, or later in one place, and every service including Mail is configured automatically.