Your phone knows where it is. Your cellular carrier knows where your device is. Do you know where your device is?
If your device is lost or stolen, you'll feel helpless without an application to help locate it. I've listed all I can find here, you're welcome to add more.
Note: for owners of Apple devices no app is needed, the feature is built into iCloud
The typical app works with a web service. You can log in and remotely:
- Turn on the device GPS.
- Lock the device.
- Wipe data.
- Make the device "scream", if it is a phone with a ringer.
- View battery status.
Note that the "wipe the data on the phone" feature requires a certain level of trust in the app provider and their security features. A breach of trust at the provider could result in someone else wiping your phone. You may prefer an application without this feature.
If your device is indoors at a the time of activation, it may be unable to get a GPS signal. If 'location via wifi' is enable, you may get a crude location out of that. Else, you may need to wait for the device to be taken outdoors with both data and GPS turned on.