I booted up my Mac this morning only to discover 6 PCs suddenly appearing on my Shared list. I recognized 3 of them as ones that my friends own. Thing is, those friends live in entirely different countries/states. The list comes back shortly after I restart my Mac. Did an app silently add some kind of VPN/tunneling networking feature over the past week? I contact them over the following: Skype, Adium, Steam (I'd used Hamachi once or twice in the distant past) What could be causing this?