While traveling, it’s helpful to be able to find a strong WiFi signal, whether you need to check your email, review your latest notifications on Facebook, or actually get some work done. You can click the little WiFi rainbow icon in the menu bar obsessively, waiting for the “Searching for networks” message to end, of course, but it’s nice to have an app running that will just scan your environment and tell you what WiFi networks are available.
I used to do this with a third-party app, like MacStumbler or iStumbler. Not anymore, though, as there’s a built-in WiFi scanner right in Mac OS X Mountain Lion.