Meta Developer interview questions

I was referred by an employee and was contacted by a hr recruiter, who scheduled a phone interview with me. From reading online I was expecting a basic screen with questions like why do I want to work at Facebook, and what I do currently. I wasn't expecting any technical questions at this stage but she did throw a basic search question, which flustered me a bit, and after a few minutes of me talking it out but not giving the exact right answer, she said she would get back to me with next steps which would either be to complete one of the puzzles on the website or to schedule phone interviews with an engineer. Promptly the next day she responded that I needed to do at least one of the puzzles and that there was no time limit, but the faster I completed it, the faster I could move on. I'm currently working on one of the puzzles.

I was contacted via email by HR saying that my friend had recommended I be interviewed for a spot at the company. I was pretty surprised by this, but have found that this is how Facebook often goes about doing things. We scheduled an interview for a few days later, which I thought was going to be a technical interview. When I got on the phone with the interview he asked me about what I've been working on recently, and so I got into this whole thing about my research project which I probably took a good 10 - 15 minutes describing. He basically just verbally nodded through the whole thing. He then asked me about what positions I was interested in interviewing for at Facebook. In my push to prepare for what I was expecting to be a technical interview, I somehow neglected to actually figure out what specifically I could work on at Facebook. I mentioned doing something with the large data sets they work on, since my research focused somewhat loosely on large-scale data analysis. Should have prepped for that one, but no problem. He then told me that he'd be happy to set me up for a phone interview with an engineer as soon as possible and I was like "whaa?! I thought you were one!". Not actually, but I did say that I'd be happy to interview with an engineer and so he got that set up for me. I'll come back and post once I've had my *actual* technical interview (instead of just an HR sanity check)