Link: Hail to the Victors: So, I stand corrected....
In response to Justin’s post about real time revision collaboration, I agree that the notion is appealing, although it may cause more trouble than its worth. If two people were working off of the same file and were in disagreement about something, one of them could go and delete parts of the file without the other person having any record of the original version. However, I’ll give you that it would be really efficient.
As it turns out, there are two sorts of systems for document sharing currently in use. One is the locking model like you describe for docushare. The other i s a non-locking, resolve conflicts as they arise model. In this latter model, multiple authors may check out document versions and alter them. As long as the alterations don't conflict the documents can be re-merged in the end. Well-known versions of this type of document sharing are CVS and subversion. Wikis, a web based collaboration system, use cvs or subversion to manage the underlying document versioning.
I had hear ctools was going to add RSS capability. Reading RSS is pretty generic and commodity-like at this stage.