A recent question asked to this blog as to whether I thought it a good idea to use a public folder as a repository for a shared calendar. My answer was “no” as I consider using a shared mailbox to be a much better response. That answer deserves some explanation, so here goes.
First, I don’t think it a good plan to make more use of public folders than absolutely possible. Some companies haven’t deployed public folders because they don’t need them to support older clients such as Outlook 2003. These companies can stop reading now as you’ve only one choice in the matter and that’s to use a shared mailbox.
Over the last decade, Microsoft has disappointed companies who do public folders because they haven’t exactly devoted lashings of care and attention to the development and maintenance of public folders. Every release comes complete with the compulsory “don’t worry, public folders aren’t going away anytime soon” announcement, but the future remains uncertain because Microsoft hasn’t added new feature to public folders for years. In addition, Microsoft hasn’t provided a migration path to other platforms (for example, SharePoint) that can move public folder data and applications in a seamless fashion. You therefore conclude that adding more data to public folders at this point might just end up with more of a migration challenge in the future.
On the other hand, mailboxes remain the natural core focus for much of the engineering within Exchange, as evident by the introduction of continuous replication over the past two versions. It therefore seems to be more sensible to use a mailbox-based feature rather than public folders whenever possible.
Second, the management and maintenance of shared mailboxes is easier than public folders. I know that Microsoft released an updated public folder administration console in Exchange 2010 SP1 that addressed some issues that had irked administrators for ages, but it’s still difficult to do something as simple as view the contents of a public folder. By comparison, the auto-mapping feature introduced in Exchange 2010 SP1 means that Outlook will open shared mailboxes automatically if a user is granted full access. I think it’s also easier for users to understand how to use a shared mailbox rather through Outlook.
Third, public folders weren’t strictly designed to host shared calendars. Sure, they’ve been hosting calendars for years and the implementation works, but the latest background features provided in Exchange 2010 don’t function with calendars stored in public folders. By this I mean the Resource Booking Assistant, Calendar Attendant, and Calendar Repair Assistant. Some of these might mean little to you or not deliver much value to the way that you want to use a shared calendar, but I’ll hazard a guess that automating the booking requests that flow into a shared calendar will be valuable to many.
Fourth, there are many more mailbox manipulation cmdlets than public folder management cmdlets. Again, this might not be interesting to you but I thought that I’d make the point anyway.
Fifth, a shared mailbox can store so much more than a calendar. For example, you could associate some shared contacts with a calendar. Sure, you can use another public folder to store contacts that you want to use with a calendar that’s in a separate public folder, but there’s something satisfyingly united about keeping all of the data in one place – the shared mailbox – if only because this makes it easier to move the data should the need arise.
Sixth, using a shared mailbox doesn’t cost you anything extra because Microsoft doesn’t require a CAL (or an Office 365 subscription) for the use of a shared mailbox. Public folders don’t cost you anything either so this isn’t really an advantage. However, I thought it worth making the point because some believe that they have to pay for shared mailboxes.
Last, a shared mailbox is not a public folder so you’ll get better and more complete support from Microsoft should anything go wrong. And you have a go-forward plan for future versions in which you can have confidence, and that’s always a good thing.
Anyway, these are just my views. Feel free to disagree.