Question : Why "msstd" is necessary in Outlook anywhere?

Why "msstd" is necessary in Outlook anywhere, like "msstd:mydomain.com"? Why I can't just put the FQDN, like:"mydomain.com"?

Thank you.

Answer : Why "msstd" is necessary in Outlook anywhere?

Check this
http://msexchangeteam.com/archive/2008/09/29/449921.aspx