We Read 150 Privacy Policies. They Were an Incomprehensible Disaster

We also collect contact information if you choose to upload, sync or import it from a device (such as an address book or call log or SMS log history), which we use for things like helping you and others find people you may know and for the other purposes listed below. Network and connections: information such as the name of your mobile operator or ISP, language, time zone, mobile phone number, IP address, connection speed and, in some cases, information about other devices that are nearby or on your network, so we can do things like help you stream a video from your phone to your TV. Location-related information can be based on things like precise device location (if you’ve allowed us to collect it), IP addresses, and information from your and others’ use of Facebook Products (such as check-ins or events you attend).

Source: www.nytimes.com