I’ve been thinking a lot about software above the level of a single device lately, so I set out this weekend to finally get two-way email synchronization working on my Blackberry.

My main goal is to have a single inbox I can access from multiple devices without having to ever deal with the same message twice (i.e., if the message is read/filed/deleted/etc. on one client, it’s marked read/filed/deleted/etc. on all clients), with full support for disconnected operation. (I care much less about the oft ballyhooed push email feature—I’m perfectly content to wait 15-20 minutes for email to be delivered.)

Since what I want more or less perfectly describes IMAP, I figured Blackberry Internet Service, which uses standard Internet protocols for mail delivery and supports IMAP, would be sufficient, and that I wouldn’t need Blackberry Enterprise Server, which hooks into Exchange and other “enterprise” messaging systems.

Unfortunately, I appear to have been wrong. While messages read and deleted on the Blackberry are reflected on the IMAP server, the reverse is, surprisingly, not true (surprisingly because, unlike POP, which behaves similarly in BIS, IMAP is a bidirectional protocol).

In other words, when messages are read or deleted on another client (e.g., the Thunderbird running on my laptop), those changes aren’t reflected on the Blackberry; so, as a result, the Blackberry accumulates every message I receive when it’s not in use, making a periodic “Delete Prior” necessary to get rid of all the accumulated junk (which obviously deletes the useful messages too, like, ahem, the ones with my flight information in it).

Worst of all, after several days of trying to figure out why IMAP wasn’t working the way I was expecting it to, I discovered this is the expected behavior (see note 5—“Messages deleted from the source mailbox are not automatically deleted from the device”), rather than a bug.

What to do? I could obviously break down and upgrade to Blackberry Enterprise Server. I’m not too keen on setting up an Exchange server just for this (which would cost hundreds of dollars, particularly after the cascading upgrades typical of Microsoft products, e.g., I’d need to get Windows Server too).

As an alternative, there appear to be a number of companies that offer a BES hosting service. However, the costs add up pretty quickly—another $10/mo. to T-Mobile to allow BES traffic through (the “business tax”), $10/mo. for BES hosting, and $10-15/mo. for Exchange hosting on top of that (BES hosting is an add-on to Exchange hosting in every plan I’ve seen). That’s a grand total of $35/mo. just to get email marked read or deleted on my Blackberry when I read or delete it in Thunderbird. Hrmmph.

Another idea is to find a Blackberry IMAP client, but there seem to be a dearth of these. The main one that comes up both in web searches and that’s described in Blackberry Hacks is from a company called Reqwireless which, tantalizingly, was acquired by Google last year but whose products, frustratingly, are no longer available. In any event, I want something that integrates with the Blackberry’s excellent inbox, which aggregates email, SMS, missed calls, Google Talk messages, etc. in a single stream, and I’m not sure if a separate IMAP client will be able to do that.

Other observations:

This page says that “two-way [Blackberry] sync is coming soon” to Yahoo Mail. However, “coming soon” doesn’t really help me.

Funambol looks very promising, but it’s going to take me a little while to wrap my head around what exactly I need to do to deploy it. Not exactly point and click.

Scalix offers Scalix Wireless Solution that works with Blackberry and is integrated with the Enterprise and Small Business Editions. At $60/user with no minimum number of users and a free trial, this looks promising too.

Zimbra offers Zimbra Mobile, which “includes the ability to leverage Zimbra’s third party mobile partners that offer two-way sync to Blackberry and other devices” (whatever that means). However, I’m assuming this comes bundled with the Network Edition, which is sold with a minimum of 25 users, and that probably makes it unaffordable to an individual user like me.

Any other suggestions?