|Reduce ability of others to trace your activity to zero. Whether it is a Chinese government or a band of thugs.|
Double VPN allows you to establish a VPN connection to one server and leave Ivacy VPN cloud from a different one. For instance, you may establish a VPN link to the Russian server but you will be visible in Internet as a user of the UK server.
It makes much harder for any third party to trace your activities, but it also substantially affects the speed of your connection: it becomes slower.
In general, we don't recommend to use this feature for P2P (and other bandwidth heavy) activities, but it makes sense if you are working with small chunks of sensitive information or suspecting that your Internet connection may be compromised.