To facebook, or not to facebook?

Something disturbing happened to me the other day, but to explain it you need the back story. So, my friend Brent decided to make me this facebook page because I refuse to join the f.b. revolution. Now, he seemed to put some effort into the page, (lots of pictures, etc) and the page was actually funny, but a little mean and patronizing. So I left it up, as, in my opinion, a fan page of me that I had nothing to do with :P because I was at the same time offended by and entertained by it. So, the disturbing thing happened a few days later. I have Blockbuster Online as all you faithful readers may know, and I decided to add the new BBC version of 'Persuasion' to my queue. When I clicked 'add', this little window popped up saying, "Your Facebook diary has been updated to show you added this movie to your queue!". Um, what? Why, why why is this being noted so the internet population at large can see my video rental habits? I felt so freaked out that this website could invade insignificant little details of my life like that and post them as a news flash. I'm sure I reacted a little too much, but I felt like my privacy was a little violated. Now this leads me to another question. What is the appeal of these social networking sites. Is it healthy to want all your friends/acquaintances/mailpersons/etc to know everything about you, like a page like that promotes? I'm still not sure.