There's a very impressive demo at http://www.mozilla.org/en-US/collusion/demo/ http://www.mozilla.org/en-US/collusion/demo/ too. One thing I didn't understand

There's a very impressive demo at http://www.mozilla.org/en-US/collusion/demo/ http://www.mozilla.org/en-US/collusion/demo/ too. One thing I didn't understand from the diagram in the article is that some grey circles are connected to each other : Is that from that that the browser sees, or is it linkages that are known to exist (outside of the raw data)?