So a few things to call out here. One, go down to the ‘messages’ section to read that note. Have you deleted a message? Guess what, it’s still there and accessible to law enforcement (allegedly without even a court order… believable but I’d need a better source to be sure). Your chat sessions are stored, though they’re not sure for how long. It also stores your location when you ‘check in’ somewhere, unsurprising. Friend requests, whether accepted or deleted, are stored.
It also has a field called ‘last location’. They’re not sure where that comes from, whether it’s from ‘check ins’ or if its actually reaping GPS data from your smartphone. That one’s nice and creepy.
Photos also don’t get deleted, just the public link is removed. People are finding they can still access them. And guess what? If you’re tagged, and untag yourself, FB still has you tagged. No surprise there either.
At any rate the list is extensive. This was just a sample, but in essence everything you’ve ever typed into Facebook (and a number of things you haven’t) get stored by them, for good. Oh, and if that’s not enough? They set a cookie that let’s them track you even after you’ve logged out.
It’s critical to remember. If there’s a service you use that you’re not paying for, you are not the customer. You are the product being sold. Sometimes that’s as benign as putting ads on a webpage for your eyes to see, and sometimes it’s not benign at all.