I know that there have been some murmurings as well about having Joyent integrate an API interface for Mailtags, which looks like an incredible idea, but again Joyent supports no offline synchronization of anything but mail itself (courtesy of IMAP, of course).

@Jesse, there’s a Zimbra test server now at my work as well, about to replace SquirrelMail as the College’s web interface and to provide a robust calendaring solution. I’ve been playing around on it, and like the look and feel of it too.

Zimbra is close, but not fully there yet as they need to implement a few more collaborative features to make it as robust as the mainstream corporate solutions…. Lack of proper delegation/shared folder support is probably the biggest limitation right now, although I do understand that they are working on it.

For smaller businesses and distributed organizations, I’ve also found that Joyent is a pretty good service. It’s entirely web-based for calendaring and address book support at this point (e-mail is available via IMAP, but there’s no Address Book or iCal sync), but it seems to have a good collaborative feel to it as long as you’re content to work almost entirely in a web-based world.

We’re far off-topic here, but for me, a solution that would replace Exchange would have to provide the following collaborative features:

E-Mail, Calendaring, Address Book Support
Ability to sync to the iApps (IMAP mail, Address Book, iCal) for offline access to all information.
Ability to share calendars and address books.
SHARED FOLDER SUPPORT. This is huge, and is a place where a lot of solutions presently fall down. Exchange Public Folders aren’t even a great solution, but are presently the only one really available to a Mac user (GroupWise did this far better, but the GroupWise Mac client is sad and pathetic). The ability to use IMAP for offline sharing of mail folders and have a web-based interface into those folders would be a must.
Basic Document Management (the ability to place free-standing documents into folders to share with other users). Mail.app can attach a document into a message, but there’s presently no way that I’m aware of to just drop a document into a folder directly.
Fully integrated mobile device support (Blackberry et al)

As I mentioned above, I’ve actually preferred the collaborative features of GroupWise in many ways, as it provides the shared folder and document management support that Exchange mostly lacks. Unfortunately, there is zero integration with GroupWise and the Mac world, and the closest thing they have to a client is their cross-platform Java client, which is not only ugly and non-Mac-like, but doesn’t even provide all of the features of it’s Windows counterpart.

Bottom line is that I’d really like to find something that can fully replace the way I use Exchange. I’m presently waiting to see what Zimbra is going to become, as it has a lot of potential, and already addresses many of the points above, but they have to ensure that anything they provide in a web-based world is also available in a synchronized offline equivalent…. I travel with a Powerbook and do not want to be tied to having to link up to the web to retrieve information that I need.

What do they run instead? Does it work in a multi-office environment? Our IT Department wants to upgrade Exchange and I want them to consider some alternatives. But the alternatives need to work well with offices in several states/countries.

Ultimately, in my experience the problem in many organizations stems from people using their work e-mail for excessive personal use. Of course, many companies could stem that tide by taking the opposite approach…. Ensure that access to external webmail services like GMail and Mac.com is NOT restricted, so that at least employees can get some access to their personal mail while at the office, and encourage them to use their personal mail accounts for personal material, rather than cluttering the corporate mail system with it.