Working on one text document with multiple colleagues can prove to be very complicated. Imagine writing a first draft and sending it out to several colleagues for feedback. You probably will receive several revised versions of that text document in return which contain annotations, comments and other feedback.
The difficult part begins to combine and make use of that feedback without loosing control. If you do that in Microsoft Word or any other desktop text editor you will most likely wind up with multiple documents opened in tabs or windows trying desperately to align them comfortably.
Text Flow is an online collaboration software using Adobe Flash and Adobe Air that allows the user to compare and display multiple versions of a document online. With Text Flow it is just a matter of dragging and dropping the documents into the interface to visualize all comments and changes made by other authors who worked with the document.
Check out the Text Flow online demo to see how the system works.
There are obviously other ways to handle the problem of receiving feedback from multiple colleagues. If time is not a issue you could make the colleagues work on one document only that gets send to each of them successively.
Other services like Google Docs offer basic collaboration features but they are not always allowed to use depending on the company you work for.

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Looks nice Martin. But wil it be a open source software after the beta?
This seems to be located on their servers… I doubt no one wants to send their .doc’s etc to those servers… so until this can be run locally without need to upload things to anywhere, it’s pretty much no use for serious businesses.
And second question goes: how many of words features are even supported by this product?
And does support currently only:
Internet Explorer 6 or higher and Firefox 2 or higher on Windows.
Safari 3 and Firefox 2 or higher on Mac OS X.
Alot open questions….
Redliner (www.redliner.com) offers another “parallel” word processing solution that really clears up the confusion of edits and comments by multiple collaborators. It also adds workflow alerts that keep the collaboration process moving faster towards completion.