Like the way that Yahoo did with their email service users, Microsoft has also recently added a policy for deleting Hotmail account if the user are left inactive after a certain period of time.
The policy has newly added to the “Service Agreement” of Outlook. Accordingly, Microsoft requires users require to sign in to hotmail account periodically, at least one time within 270 days. If not, the account will be canceled and the data will also be permanently deleted. In addition, the email accounts are deleted after 360 days will be available to the public again. This information is not mentioned in the Service Agreement, however it was shown on a number of Microsoft blog.