Open source free software collaborative real-time text editor

I was thinking about this again at the ONA conference--

Wouldn't it be great to have an entire room of people, many of us compulsively taking notes, doing so on the same document?

With the capability for public or private side notes, but the main text would be a rock-solid bulletted abbreviated transcript?

The technology would have to be doing some monstrous artificial intelligence to try to merge stuff typed at the same time, but imagine... would people sort themselves out a little bit by typing speed?

Or in this context, if simultaneous editing and combining is impossible, some interesting things could come from a sophisticated program to merge (parts of) timestamped note transcripts, after the fact, with time for the computer to think.