Quite simple actually. It all depends on what the program does. Viruses want to spread themselves, what better way than the internet? Weird unknown program trying to dial out? Little Snitch intercepts and asks you whether that is allowed. Same goes for spyware, after all someone wants that data... Malware can install spam servers, porn servers, botnets, etc. They all want to chat with the rest of the world. In other words, they all have to get through Little Snitch. Now it's your turn... Don't automatically approve of every program connecting to another computer. check what the program is and whether it would be normal for the program to call out to someone. If your freshly downloaded screensaver wants to dial out... Why? You draw the conclusions.