SubEthaEdit (formerly known as Hydra) is a revolutionary text editing application for Mac OS X. Written entirely in Cocoa, Apple's Objective-C programming environment, it offers collaborative editing via Rendezvous, Apple's network service autodetection system, but also allows greater internet connectivity (over port 30729, for the curious). Included in the application is a Safari WebKit-based HTML/CSS preview system, making it perfect for group web design.
For those uninitiated, collaborative editing allows multiple users to convene and work together on a body of text. It is a fairly new idea, though Gnu Emacs has included a rudimentary version of it for some time. It provides a communal developing environment that allows all connected users to view changes to the document instantly, instead of the more delayed updating available through more conventional means like CVS. The system is both scalable and flexible, and has widespread application, ranging from school research papers to web design.
SubEthaEdit also includes all of the features expected of a more technical text editor, including context highlighting and automated indentation, and uses color-coded highlighting to show which user contributed each part of the file being edited. These features streamline the editing process, and make the application a viable text editor, even without the inclusion of the collaboration features.
It is clear that the developers paid close attention to the Aqua Human Interface Guidelines, as the interface and flow of the program are clearly user-centric. This means that the program behaves similarly to iChat (Apple's AIM-based instant messaging application), for instance displaying user icons and names in a side drawer.
SubEthaEdit has been honored with a number of awards, among them Apple's Design Award in the Student Developer category, as well as the O'Reilly Mac OS X Innovator Award. It is available at no cost from The Coding Monkeys (http://wwwbruegge.in.tum.de/projects/hydra/subethaedit/), though it is not an open source project at this time. For more information, please visit the site noted above; The online documentation is fairly comprehensive.