What data "leaks" that a moderately sophisticated/equipped adversary could not easily learn via other means? In 45 seconds I was able to learn your name, basic age/location, and email from this post, your hn profile and github profile. Another 45 seconds and I found your google+ and twitter accounts, with better location data, education history and employer.

Most people aren't moderately sophisticated/equipped adversaries. They are just people you think have no business knowing about (parts of) your life.

Anybody who could or would actually harm you with the knowledge can easily acquire it is the GP's point, I think. A Facebook account, ipso facto, adds no additional risk.

Its not what people can know about you, but rather how much of what they know is controlled by you. You can put out there all the info you want to make public, but if you change your mind, facebook will still keep your data.

He was in control of the data and then he relinquished control of the data when he shared it with facebook (and google, twitter, github and HN).

Trusting facebook to prevent Eve from accessing to your data is not the same thing as controlling Eve's access to your data.

Everything you mentioned is actually data I've purposely made available, EXCEPT for the twitter account, which continues to vex me. I haven't tried to delete that recently; I'll try again soon. (I can't remember what happened the last time...)

I still am curious about the information that a "absolutely bare" FB profile leaks?

People that don't understand that I do not like FB are not my friends.

I used to think this, but the truth is more complex. Facebook makes it easy for a lot of people to manage very large number of friends. If you're not using Facebook but most people around you are using it, even though your close friends would probably care enough about you to communicate with you through some other means, you will probably be missing out on a large number of distant acquaintances.

The usual counter-argument to this is that it isn't worth it to care about such relationships anyway, and that you should only be concerned about close friends. It is true that close friends are important, but it might not be true that the optimal strategy is to care only about them. It may be useful to keeping distant connections with old friends in case you ever run into them again, or to have a large distant social circle with diverse backgrounds and physical locations to get more diverse recommendations, opinions, help, etc. More dramatically, say you arrive in a new city where you don't know anyone and no one knows you, but most people use Facebook: if you insist that people that don't initially know you should use your favorite communication medium rather than Facebook to interact with you online, it might be harder to get things started.

This isn't to say that you should use Facebook: I never used it and discourage people from using it. This is to argue that you should be conscious that not using Facebook may come at a personal disadvantage. I personally still think that it is more important to stick to my principles and make an insignificant effort to improve things by not being on Facebook, but I can understand that other people might think differently (though I disapprove their choice).

If you are not going to be happy if you are not honest to your beliefs.

Not true. You can be really honest to your beliefs and have a miserable life specifically because of that.

I have deleted by FB account twice and then I was spending lots of time explaining why, getting weird looks from people and being left out of comments (e.g. people would post something to FB and be laughing about it later but never explain about what.. really impolite of them but what can I do? engage in more arguments).

So yeah, be honest to your beliefs, just don't expect that will translate to happiness (unless you really work on telling yourself none of that unpleasant situations are really bad). We are human beings, how we interact with others matter (even if I didn't want any of that).

Well for me, sharing my beliefs with friends makes me happy. If someone does not share or respects my beliefs, then there is no sharing and understanding each other which is the essence of a friendship.

No matter how strange your beliefs are, you will always find people that think similar. The world is very diverse.

It seems that FB even changes the fundamental meaning of a friend. Which is a shame and a lack of social culture.