This article from the Engadget web magazine discusses how your online searching behaviors might be monitored by different companies that you are unaware about. This data is likely used to build profiles that may impact the advertisements you see, credit ratings received, and other potential social network aspects as of yet identified. 

From the WSJ article:

Some people list emergency contacts on an implanted tag. And others see potential for the use of the tags in medicine, though one big challenge needs to be addressed for those visions to become reality: Medical personnel or anyone else trying to help someone in a medical or emergency situation will need to have some way to know that the person they’re trying to help has potentially lifesaving information available under his or her skin.

From the Federal Trade Commission website:

If you have a smart phone or other mobile device, you probably use apps – to play games, get turn-by-turn directions, access news, books, weather, and more. Easy to download and often free, mobile apps can be so much fun and so convenient that you might download them without thinking about some key considerations: how they’re paid for, what information they may gather from your device, or who gets that information.