Pocket PC Thoughts: Picking the Right Email Strategy for Your Windows Mobile Device

IMAP/IMAP4 E-mail Accounts
IMAP, also known as the Internet Message Access Protocol, was designed by Mark Crispin in 1986. It's similar to POP in that it's a widely supported protocol, usable in Outlook and in Outlook Mobile on Windows Mobile-based devices. IMAP isn't as widely supported as POP, largely because it requires more server resources to support. Most ISPs do not offer IMAP as an option, but most Web hosting packages that include e-mail hosting will offer IMAP alongside POP. In fact, many e-mail accounts nowadays can be accessed via POP or IMAP, depending on how you configure your e-mail client. It's best to stick to one method rather than mixing them. IMAP is an improvement upon POP in many ways, but the core advantage is that all your e-mail remains on the server. If using POP results in all your e-mail being collected and held on the local computer in an Outlook PST file, IMAP is the opposite—all the e-mail stays up on the e-mail server. Copies are downloaded to your local computer and cached for offline use, but the server is where all your e-mail really lives. Another key advantage is that IMAP supports sub-folders, meaning you can sort and archive your e-mail, all on the server.

The advantages of this are immediately obvious when you configure Outlook on your desktop and Outlook Mobile on your mobile device so that you can access e-mail via IMAP—both devices show all the available folders, and download the e-mail you specify. The power of this solution can't be overstated. Whenever I set up a new computer or Windows Mobile-based device, I enter in my IMAP e-mail account settings. Within seconds I have access to all my e-mail, even though it's spread over dozens of folders. On a Pocket PC I can select Tools > Manage Folders and see all of my e-mail folders. By checking off the box next to the folder I want, I can download all the e-mail in that folder. This can be extremely useful if you need to access old e-mail sitting up on the server.

IMAP is not without its limitations—most IMAP accounts can only be accessed by one e-mail client at a time, so if you leave Outlook open at work and access your e-mail from a Windows Mobile-based device it may connect, then disconnect and give you an error statement about the account already being in use. And IMAP works only for e-mail, so it can't keep your Contacts, Calendar, and other Outlook data in sync.

There's also some peculiar behavior with Outlook Mobile and IMAP. When you switch to an IMAP account with Outlook on the desktop, it immediately connects and downloads all new e-mail as it should. It stays connected until you exit from Outlook, and any changes you make (moves, deletions, etc.) are tracked because you're connected to the server. However, Outlook Mobile doesn't automatically connect when you switch to the IMAP account. You'd think that tapping Send & Receive would be the right thing to do since that's what you do with POP e-mail accounts, but it's not: if you do a Send & Receive, Outlook Mobile will connect, grab your new e-mail, and then disconnect. Any moves or deletions you make will not be reflected on the server until you do another Send & Receive—and sometimes it doesn't work properly, resulting in duplicated and un-deleted e-mail when you start up Outlook or connect the mobile device to your e-mail account again.

Avoid this by tapping the Connect button when you want to check your IMAP account. Then you interact with your e-mail (read it, delete it, etc.), tap Send & Receive once, then tap Connect again to disconnect. Also, if you're connected to large folders Outlook Mobile sometimes disconnects randomly from IMAP. You need to watch the Connect icon and ensure you're always connected when making changes. Lastly, with IMAP folders containing hundreds of e-mail messages it will often re-download the same messages each time you connect. Based on my experience, IMAP works best on Windows Mobile-based devices when there are less than 200 messages in the folders you're synchronizing.

IMAP is a great solution if you want to access e-mail from more than one computer—for instance, a desktop and a laptop. I access my e-mail accounts from two desktop computers, three laptop computers, and two Windows Mobile-based devices, all using IMAP. It's less reliable on the mobile devices, and since it doesn't support Outlook data synchronization such as Calendar and Contacts, you still need to synchronize your mobile device with just one of your desktop or laptop computers. Now that ActiveSync 4.0 no longer supports wireless synchronization with a desktop computer, this means physically connecting your Windows Mobile-based device each time you want to sync—unless you're doing an Exchange ActiveSync, which is my preferred solution.