The blog-o-sphere has been bombarded with recent announcements regarding Zimbra and its up-coming desktop application.  In fact, we even have a podcast from Michael over at TalkCrunch regarding the new release, as well as the following blockquote from TechCrunch:

Zimbra will announce a new offline client application, Zimbra Desktop, later this week. It will allow Zimbra users to access and use Zimbra’s email and other office applications, in the browser, when offline.

Offline access to web applications (and just as importantly, web-based data) is an area getting a lot of attention right now. Firefox has announced that Firefox 3 will allow sites to work offline by accessing local data-stores. New startups like Scrybe are experimenting with this offline syncing. Adobe (and competitors) has just released it’s Apollo platform, which lets developers run HTML, javascript and Flash code outside of the browser and when offline.

Zimbra Desktop does not include drag and drop functionality into the browser (for, say, dragging an attachment into an email), although the company says it will be included in a future release.  All Zimbra source code, including Zimbra Desktop, is open source - I expect other web developers to be taking a close look at how they are architecting things.