Depends. Let's say, for example, you find a hole in a corporate webapp, say a wordpress application. You want to get usernames and passwords, but said app is fi

Depends. Let's say, for example, you find a hole in a corporate webapp, say a wordpress application. You want to get usernames and passwords, but said app is firewalled off and you don't want to rouse suspicions. So, you send an email to Joe over in accounting, with a link to a game of some sort that asks to start a webserver. Now, FlyWeb makes its presence known via mdns, and the compromised server now has Joe's IP address. The server can now use Joe as the patsy/proxy, and your code can potentially stay on the server just a bit longer. Yes, it's a bit convoluted, but it's the first sort of attack that came to mind. An open web server, even if local, can cause a good number of problems, especially if it's running untrusted content.