Sometimes seeing is believing. The FaceNiff Android app, released earlier this month, allows anyone to snoop on traffic on Wi-Fi networks and even hijack Facebook accounts. Sounds bad, but this video demo drives the message home by showing just how easy it is to do:

The app, which works on Android phones that have been rooted, offers “one-touch hacking,” says Kevin Mahaffey, founder and chief technology officer at mobile security firm Lookout. The technique isn’t new–it’s akin to a mobile version of the Firesheep Firefox extension released last year–but it makes it super easy and mobile.