How do you like those odd people who, completely out of the blue, standing next to you while waiting for a bus, turn to you and announce, "My name's Bill. What's yours?"
(OK, I'm rather odd for a security maven, and I usually answer. But ...)
Well, Facebook is going to make that easier. They are going to serve up "people you may know" based on physical proximity.
(You, know. Just in case they aren't already intrusive enough ...)
It is interesting that you mention this because it is being done in an appearance to make computers more helpful to you without considering that you may not want the help. I am reminded of an incident that happened early in my career when I was painting aircraft. A co-worker of mine was helping someone who asked a question about an aircraft part with which I had previous experience with. In an effort to be "helpful" I came up an inserted myself into their conversation and left feeling that I had done a good deed and "helped" both of them out. My colleague came up to me later and said that he was upset that I came over there and "butted in" on something in which he had complete control of. He wasn't struggling to answer the question and he didn't ask for my help, I just came over and offered it on my own. He stated that it made him feel like, to the customer, that my co-worker didn't know what he was talking about or wasn't going to be able to handle the question so I had to come over and correct him. Basically he felt like it made him look incompetent to the customer. I had no idea that my "helping" could be taken as such. In my mind I was going over to help the situation. I apologized and thanked him for having the courage to have the difficult conversation with me instead of just holding it in and hating me for it. I changed how I "helped" people in the future.
What if my daughters are standing next to a convicted sexual predator and Facebook thinks they need to help my daughters get to "know" their new neighbor? I think this can open up so many unwanted consequences in the guise of "helping" you be more social. Facebook doesn't know all of the idiosyncrasies and character traits (or lack thereof) of the people it is trying to connect.
I say no thanks.