Once, while at a hockey game in Colorado I had this idea that I wish the stadium could be filled with people all thinking about the same problem and trying to solve it. This result is astounding, and shows the power of mobilizing many people to think.
I suspect the trick is harnessing them in the right configuration. Otherwise you've got the old (n^2 – n) / 2 problem.
There's no way for everyone to talk to everyone. The solution I came up with at the time was to have a rudimentary chat bot connect parts of conversations intelligently. Now, of course just throw an AI at it.
A well designed website with different conversations going on in different places might work almost as well. This site does an adequate job actually.