What is our privacy? What do we trade it for?

I just read an article at ZDnet.com with the thinks that I'm thinking about. Here is the article:

Is privacy dead, or just very confused?

The article just asks the questions about our privacy on the internet. The thing we missed out in those last 10 years when the internet started to step into our lives and bombed us with newer possibilities and services was the time to sit down and think about it. In the general mindset of the people there is no shared understanding of what is appropriate to post/upload/share/tag in general. And I was very rarely in an open discussion about this topic in my surrounding, and that bothers me to.

Just thinking about the on hand problems with tagging - you have no option to influence someone tagging you on a picture. While you can additionally remove the tag, the time between you noticing yourself tagged on an embracing post and actually taking steps against it can be already to late, not to mention the fact, that if you have a lot of common friends with the person who uploaded the pic, then it doesn't help much either...
This is the side of a tagged person, on the other hand the person who took the pictures has to make a hard time creating permissions for just those people who he wants to share the pictures with.

Of course the possibilities in advertising and marketing are also huge. I like the idea, that Facebook implemented now, which gives me the opportunity to forbid applications to use me as a reference for advertising their services. (Like: Join MySuperApplication and do something to your friend Anonymous...)

I'll need to sit down someday soon and get a clear point on the does and don't on all the social networks I use. You give something and you get something in exchange, but it would be stupid to share ones life with the internet.