Summary of “Here Are 18 Things You Might Not Have Realized Facebook Tracks About You”

Information from “Computers, phones, connected TVs, and other web-connected devices,” as well as your “Internet service provider or mobile operator”.
Information about “Nearby Wi-Fi access points, beacons, and cell towers” and “Signal strength” to triangulate your location6.
Contact information “Such as an address book” and, for Android users, “Call log or SMS log history” if synced, for finding “People they may know”13.
Information “About how users use features like our camera”14.
Information through your device’s settings, such as “GPS location, camera, or photos”.
Information about your “Online and offline actions” and purchases from third-party data providers.
Facebook is unique in how much it collects from the devices you use and the websites you visit when you’re not on Facebook, using a small piece of Javascript code called the Facebook Pixel and the “Like” and “Share” embed buttons on websites.
In its written responses to Congress, Facebook dispelled the theory that the app is listening to your conversations by tapping into your device’s microphone, stating that the app “Does not engage in these practices or capture data from a microphone or camera without consent.” But when asked, as a follow-up question, if it would commit to not doing so, it dodged the question, by referring to the previous statement.

The orginal article.