Another user posted a link to a page explaining Collaborative Diffusion. From what I understand, its like influence maps, but once an agent passes through a node, that node's influence becomes zero, signifying its impassable now that he's there.
So I tried implementing it in Unity here: http://dl.dropbox.com/u/25260770/PathfindingTest/WebPlayer.html (you'll need to install the Unity plugin for your browser).
Left click to set the new attraction point or whatever its supposed to be called.
I'm pretty sure some of my code is a bit naive. Its only in certain situations do the agents will exhibit flanking behaviour. Some agents end up stuck, and I don't like the bee-like zig-zag movement they make.
Also I think it would be better to couple this with typical A*, such that, the path created by the A*, the area of the influence map that that path takes up, will be set to zero influence. Its as if the agent will be saying "to my allies, this is the path I'll take, don't cross it, its mine only. find your own path".
