Hah, yeah. I put things in this category: people I don't know about or care about at all, people I know about but don't care about at all; acquaintances somewhat falls into the latter category. Then there's people hate and I care about because I hate them with my guts and I somehow can't seem to stay away to revel in their misery. The word bekant is pretty old-fashioned over here and not really used anymore although there's the word "vän" and then there's "kompis" and "polare" which is a slang, the latter is probably the best translated into polare = buddies, To be a vän is something distant, not quite acquaintance but not really friend either to me, although it is the best translated into friend, but I make the distinction between good and close friends and to me a friend is really only a friend if they are good or close friends.
It's the same with me. When I was in high school, my brother would say, you have stupid friends. Meaning the people who were in my grade that I was on speaking terms with. When I would say, they're not my friends, he would look at me like I was crazy or heartless or I don't know what. (He's INFP 6w7 btw). And you know, a lot of those people might have seen me as their friend. People take it the wrong way being called "acquaintance". That's a good thing though. I view "Bekannte" or acquaintance as neutral, but leaning more towards a positive connotation. Acquaintances are people that I see and talk to on a daily basis. What people don't get is, if I don't like someone, I'm not going to take the effort to talk to them. If I don't like you, you're not an acquaintance, you're "that asshole". To be considered a "friend", there has to be a deeper connection than "hey we hung out a couple times and got along".
I tend to divide people in my mind as "family", "(close) friends", "Bekannte/acquaintances" (this could include people from work, people I went to school with, people I know from church, old friends of the family, etc.), "people on Facebook who I would never interact with again if Facebook didn't exist" (includes same people groups from the Bekannte category, but those that I'm either indifferent towards or find a little annoying, but have never had a problem with personally), "people who I refuse to interact with even on something as banal as Facebook" (no thank you Facebook, I don't need to suggest "people you might know"...this category should really be called "people you know that you didn't add on purpose").
I would be interested in seeing research on how the Facebook phenomenon has redefined how we view the concept of friendship.
Then there's also the distinction family and relatives (in English relatives is more interchangeable with family but in my country family only denotes the closest family members being parents and siblings) but I separate this from friends because as much as I'd like to be friends with my dad the way I view family and relatives is very distant. I think other people would think I'm a cold and heartless bastard for not caring more about them (like I mentioned in the Shit 5s say thread, it sounded like my grandmother would choke because I didn't give two damns about my cousin having twins). So to me, family and relatives are simply people I am related to by blood so they mostly fall into the category of people I know but don't really give a damn about.
Also, any bets that Mark Zuckerberg is a soc 5? I'm very selective about the people I add on Facebook and I add people I have personal interest in. If you got personal interest in me too bad, if it's not mutual.