In this post I will be showing you the difference between Exchange 2003 and Exchange 2007 public folders. Both screenshots below are using Outlook 2007.
Below is an Exchange 2003 mailbox:
Below is an Exchange 2007 mailbox:
In exchange 2003 by default everyone has full details to view your callendar. In exchange 2007 by default everyone only has permissions to view your free-busy information only. If you move a mailbox from exchange 2003 to exchange 2007, it will change from full details to free/busy. People that could view your entire calendar will now only be able to view your free/busy status!
Please take note of this before migrating mailboxes!
Additionally one more thing, if a user complains free/busy is broken, make sure the user they are trying to view has not disabled their freebusy status. Also take note for exchange 2003 users, free/busy takes 15 minutes to update itself where exchange 2007 uses the availability service via IIS so it is very quick!