IPhone – Find My Phone and Deleting iPhone

Lost mode combined with iOS 7 is extremely useful as long as th phone has cellular service or is connected to WiFi networks that it trusts. The device needs to connect to the Internet to be re activated after wiped, at which point it will enter lost mode and refuse to work again without your password for Apple ID.

Be sure to not remove that device from your account since that makes the device far more risky and expensive to sell, pawn or try to use by the thief or even someone that ends up with the device. Someone could desolder the CPU and try to reserialize or cannibalize the parts, but the quick hit of cash for a stolen device is defeated by Activation Lock and Lost Mode features.

The device shows as offline when it hasn't checked in recently to the Apple servers despite an attempt by the Apple Push Notification service attempting to send a check in request to the last active address of the device on the Internet.

If the device ever gets connected to Wifi or cellular data reconnects it, your Lock request will get sent, acknowledged and you'll get an email. If you are quick, you can log in to find my friends and see if the location data updates as well at that point.

With Find My iPhone activated this disables an activation when the phone is wiped from a different computer. The person would have to know your AppleID and password in order for the phone to be activated again (meaning use a SIM card and get reception). If they erase it, you should still be able to see the phone on your map. I would recommend not wiping the phone rather track it.

The commands become active the next time the device is powered on and gets a connection either via open WiFi or cell tower.

You won't get much in the way of information in regards to what they are doing with it. Tracking really is your best bet since it records the routes and allows you to follow the device, wiping it could make it easier for them to break into the phone and use it without your permission.