Privacy extensions means that every host on your network picks a random IP to make outbound connections from. They pick new random IPs periodically (by default

Privacy extensions means that every host on your network picks a random IP to make outbound connections from. They pick new random IPs periodically (by default usually after 24 hours), while keeping the old ones for a short period (by default usually 7 days) so that existing connections aren't broken. Rebooting or connecting to a new network will also remove the existing privacy addresses and generate new ones. Remote servers will see the privacy address, but they won't know which machine the address belongs to. The addresses will also be abandoned after a maximum of a week, so you can't trawling through your old server logs to find active v6 addresses either. They'll still be able to see what network you're coming from, but that's not something that NATing outbound connections from your network would help with anyway.