Thieves make off with millions of dollars' worth of laptops and mobile devices every year. Most stolen gadgets go unrecovered, but tracking software can help. The software runs in the background of the operating system or, with some services, the boot-level layer, which makes detecting the tracker much more difficult. Services like Prey provide free software for up to three laptops or Android devices. BlackBerry, iPhone or iPad owners can use GadgetTrak (from $4).
Most services can send a command from their servers to the device to disable it—or do something more dramatic. When the thief connects to the Internet, the program can erase or encrypt personal data, sound an alarm, or even snap a photo of the thief using the device's camera. The software also logs the IP addresses that the device has connected to since the theft and attempts to determine its location based on its Wi-Fi, 3G or GPS connections.
That location data is useful, but most tracking services won't actually work with the authorities to try to get the device back for you. For assistance with the recovery process, use a service such as LoJack for Laptops (from $40) or, for iPhones and iPads, Undercover ($5). Once the owner has alerted authorities to the theft, agents from these services give them the computer's probable location and the likely identity of the thief. Some laptop makers, including Dell, offer track-and-recovery services with personal assistance as well.