Apple's Activation Lock Feature Reduces iPhone-related Theft Report Says.

Apple's Activation Lock is one of the best security features for a smartphone to date. It was designed to prevent anyone else from using your iOS device if you ever lose it. It is considered one of the selling points of Apple products running iOS 7. This feature was introduced  as part of iOS 7 last year during the Apple Worldwide Developers Conference 2013. Just recently, New York Times published a blog post highlighting Activation Lock as a contributing factor to the significant reduction of iPhone-related theft in New York, San Francisco and London.
How does activation lock works?
Activation Lock is enabled automatically when you turn on Find My iPhone in iOS 7, or when you upgrade to iOS 7 from a previous version of iOS that has Find My iPhone already turned on. To turn on Find My iPhone on your device: Go to Settings. Tap iCloud.

With Activation Lock, your Apple ID and password are required before anyone can turn off Find My iPhone, sign out of iCloud, erase and reactivate your device. It's impossible for anyone to reprogram your iOS device, with Activation Lock feature turned on, without your Apple ID and password. As an iOS owner, it's your responsibility to memorize your Apple ID and password and never share it to anyone for you own protection.
Scenario What if you bought online (i.e. from Sulit.com, Ayosdito.ph, etc) a second-hand iOS device running iOS 7 but you are not aware of iOS 7's Activation Lock feature? You didn't know that the device you bought was a stolen property and the original owner of the device used the Activation Lock feature to erase and lock the device you just bought? It was until you connect to the internet using WiFi or using the device's 3G/LTE data connectivity and the device played an unfamiliar sound and locked with a passcode that you don't know. Suddenly, the device displayed a message on the screen saying that the device you just bought is reported lost and you need to contact the original owner using the number displayed on the screen. What will you do next?
The above unfortunate scenario is a common Activation Lock problem of people buying second-hand iPhones from deceptive online sellers. Always be extra careful when dealing with people you personally don't know.
A Friendly Reminder It pays to be knowledgeable about the product that you are going to use. Before you buy anything valuable, make sure you do a little research about it.