WiFinder is a one-screen application that scans all of the local WiFi networks. It determines if they're locked (reporting which lock type to you) or if they're open. If they're open, it attempts to associate with them and open up Google's homepage. If it gets a result, it checks to see if it was actually from Google or not - many "open" networks actually require authentication, and redirect you to a login page. If it is from the right server, then the status icon is updated with a green check mark. Otherwise, you'll get either a red X (for redirected) or red - (for locked).