The "CDF Concept", if I remember, was (is) to allow streaming collaboration and cloud publishing, that is, being able to show (part of) a notebook to colleagues real time, steaming, if they are connected, even allowing remote software to connect and receive realtime cloud updates. The entire concept was not "display whole notebook to a colleague" which was considered "old fashioned". However, the new Front End does cloud publishing and web server streams and cloud publishing. I'm unsure how CDF can trump that game either. Personally, I see front end has "end user collaboration tools" but people share work in Wolfram Communities in old fashion form! And then also, while many upload CDF or view on the wolfram demonstrations site - these are not real-time. I'm at a loss as to whether CDF can achieve its goals and not be a copy of the Front End by the time it completes it.
And still, we share our work, questions and answers, not using Mathematica's built-in collaboration tools, but a silly blog website (that's moderated!) It's bound to be that way for the fore-seeable future. Who would store the contents and make it all searchable? Why do people keep coming back to blog websites to communicate if they have advanced collaboration tools?