Microsoft, in an e-mail sent to members of its free Hotmail e-mail service yesterday, has announced that accounts will be closed if they are not used at least once per month. As part of the deactivation, all messages, folders, and contacts are permanently deleted, according to c|net. The inactivity rule does not apply to MSN Hotmail Extra Storage accounts, which cost US$12.95 per year and provide five times more storage space than the free accounts.