Since thought nodes are not anchored, the user cannot maintain a "breadcrumb" visual frame of reference as he follows a topic trail. Meandering through the What Should Obama Do trail gave me vertigo.

Better the flexible anchoring system of Compendium if you want a network representation of the dialog.  I.e. Anchored network that can be adjusted by a facilitator.

Also check out the deepamehta project.  They are explicitly working on an anchored node topic map construct for the purpose of visual continuity.

The new visualization tools are great.  But they invite overengineering.

Great job though on your efforts.  I think this is a terrific initiative.

Steve Mack
Washington, DC