Ipv6 allows for stateless configuration of a interface. The IEEE (aka MAC or hardware address) is generally used to generate tentative addresses which commonly end up being the assigned address provided stateful addressing does not exist on the network (such as DHCP.) This is the case in OpenBSD's import of KAME.
Since the same method to generate an IP is used over an over (the host has an unchanging, persistant address,) the traffic generated and recieved by hosts would be open to many forms of analysis not necessairly confined to the computing world. For example, when some is at home, at work; what they access could be more easily tied to them (and the hardware they use,) decreasing anonymity. The problem and solution are outlined in RFC 3041. http://www.ietf.org/rfc/rfc3041.txt The solution is to use random data to generate ipv6 stateless addresses. Trying to be productive and not an asshole, Travers Buda
