MSN ages out Passports that have been inactive for a while. Hotmail for instance, temporarily disables a free account -deleting its Inbox- if nobody has logged into it for 30 days, and deletes the account some time later (Premium accounts are not affected). Its contact list is deleted after 60 days and (since late 2004) the address is also removed from its buddies' MSN Messenger lists for a complete cleanup unless there's additional information about the contact such as phone numbers. Names of deleted Spaces are not recycled into the system for at least 60 days.

These are all efforts to prevent the possible hijacking of unused member names. Imagine you start sharing childhood memories with an old friend on MSN Messenger, only to find out that in the meantime someone with the same name took his place on your contact list...

(Time spans are subject to change as MSN continues to monitor the usage patterns of its services and gather customer feedback)