You will got crazy trying to build a map, is a dynamic network, users got away and new ones enter. If a user goes away it doesn't mean that he turned off the computer, only that your computer cut the link from him and had established a new more favourable link with another. Most of the users have dynamic IP and not static as with sites, a dynamic IP is renueved every each hour, so it can remain the same or can be other one. Neither the Gestapo nor the KGB will be able to do the task. For ending you must remember that be linked to a P2P is not something illegal, P2P networks are like a knife, a knife is a very useful tool and also can be used to kill people!

Stupidity also evolves!