It was hard to see, that InCopy is still using E-Mail to collaborate with editors on another place. I thought it's all in the CC!! For this is a must have: I'm sharing an InDesign-document (or parts of it) save it for my incopy-editor. The editor gets a notification (email or instant) and will open it and makes changes and new content, save it and the designer gets a notification that there is new content from editor xy. He can now accept this and the new content is inside the InDesign-document. Finish.
But ash the moment it's very hard to check out/in make assignments, export it directly or as package. And saving on dropbox produces many errors/bugs (can't work in text-frames in InDesign nor InCopy …).

Please, make it real user friendly and smart for small teams over the world! (I thought it is, when I step into CC!!!)