Karen writes, "I met someone for the first time in a meeting the other day. A few hours later, she showed up on my Facebook page as 'someone I might know.' I've also noticed that people sometimes pop up in this feed shortly after sending me emails. How does Facebook know about these interactions? Or am I just being paranoid?"
You're not being paranoid, Karen. From what we can tell, Facebook has someone spying on you at all times. That secret spy is [insert dramatic music here]: your smartphone!