Lets say you are running something over VPN,
and VPN suddenly fails, then this will kill the app you dont want to connect via the normal interface.
Its just a small ruby script you can put into e.g. /usr/bin/
vpn-fuse VpnName 'killall secret-app' vpn-fuse BankNetwork 'killall bank-client' vpn-fuse iPredator 'killall transmission-gtk' ...
so far only tested on Ubuntu…