If you use Outlook Express to access Hotmail, this is for you:
As a valued customer, we want to provide advanced notice that as of June 30, 2008, Microsoft is disabling the DAV protocol and you will no longer be able to access your Hotmail Inbox via Outlook Express. As an alternative, we recommend that you download Windows Live Mail, a free desktop e-mail client that has the familiarity of Outlook Express and much more.
I guess I always thought Hotmail connectivity was via IMAP, which many email clients can accommodate. Apparently not; Hotmail and Outlook Express actually use a protocol called DAV — Distributed Authoring and Versioning — which Microsoft is disabling because it’s outdated in this age of multi-gigabyte inboxes.