Open-Xchange is exactly what the name might suggest: an open-source competitor to Exchange. It’s one of the businesses that has both a free (GPL) version and a proprietary, expensive version. Note that the free stuff doesn’t work with Outlook, meaning that it’ll be a great web-based groupware solution (e-mail, contacts, calendar, to-do lists, and even file management, and any of that can be shared with other users on the server), but that it won’t interface with Outlook. There’s a demo of the web GUI here, which seems pretty spiffy. (It’s the non-free version, but the functionality, from what I’ve read, should be the same, or at least similar.)

Open-Xchange appears to sit on top of Postfix for SMTP and Cyrus for IMAP: it’s a spiffy interface to existing (popular, arguably best-of-breed) technologies, instead of trying to write a mailserver from scratch. This means that ‘normal’ mail clients can access the e-mail too. It also means that ‘normal’ server stuff can be dropped in: MailScanner for anti-spam, for example. (Aside: I didn’t know that SpamAssassin includes Bayesian support now.)

However, Open-Xchange is severely limited if it can’t work with an Outlook client (IMHO). I also use GMail for e-mail and calendar, and use my Treo as my primary calendar and contacts database. So it’s getting to be this big mess with things existing in many places.

So enter Funambol. It’s normally described as being something for syncing mobile phones: contacts, calendars, and all that, too. However, I view it as even more novel: it includes a lot of connectors, so that, to me, its best quality is that it can function as a synchronization layer. It’ll sync with Open-Xchange via a connector, meaning that I could update contacts in Open-Xchange and get them on my Treo. (It also includes an Exchange connector.) And there’s a connector for GMail, too, meaning that it might just be possible to get all the places I keep my contacts and calendars and to-do lists to stay synced up.

And, Funambol includes Client Plugins for not just things like Windows Mobile, Palm, Blackberry, iPod (?!), and iPhone, but also for desktop clients like Outlook and Evolution.

I’m sure it won’t work out quite as perfectly as I’m dreaming it can. I’m already starting to doubt the Google integration: it seems the connector might just be for contacts, for example, when what I really want is Google Calendar.

And on the subject of “the cloud” and syncing your data between devices, Kyle’s comment about how he was running his own Mozilla Weave server got me curious. There are some directions on how to set it up here. (Note that there isn’t a “Weave Server” software product per se, it’s just a browser plug-in that communicates with a server using WebDAV in a specific manner. It can do encryption, too, it seems.)