OpenGroove is a collaborative software program that allows users across multiple locations to synchronize data. Users can create workspaces, and share those workspaces with other users. Users can also send message to one another. Each message attachment can be up to 2GB, and the total size of all attachments can be up to 2GB (this total limit could be further raised to 16TB with some trivial code changes, which I plan on doing later on), and folders as well as files can be added.
OpenGroove is still a work in development. Currently, you can add others as contacts, and see when they are online and offline. Support for messaging between users is almost done. Workspaces do not work right now, but I'd expect to have them back working soon.
OpenGroove's main website is located here.