One icky thing about linkedin. I moved to London as a sort of "young professional" and moved in with two other similar people. I was working at a big tech, my flatmates were at a soft drink startup and an NGO respectively. We had zero connection before and no common friends or colleagues, totally different industries. But linkedin recommended us as contacts. The only information it could possibly have been using is our shared IP address. I mean I guess it's not that surprising but it gave me a bad feeling.