Although I have used and enjoyed Blockbuster's online movie rental service for a couple of years now, today I fired them.  Here's the letter I sent to them:

To whom it may concern,

Yesterday evening, I decided to add a few movies to my Blockbuster queue. Upon adding movies, I was surprised to see toasts from Facebook showing up on the Blockbuster site indicating that something was being added to my Facebook news feed. When I finished adding movies, I went to Facebook to see what was going on. I was then quite surprised to learn that Blockbuster and Facebook were conspiring to broadcast my movie selections to my Facebook friends.

I am not normally uptight about privacy issues, but you guys really crossed the line on this one:

• I had never told either Blockbuster or Facebook that you should share my movie selections with friends.
• Neither of you asked me if you could take this action. You just went ahead and did it, assuming that I would not mind.
• This sharing of information about me without my informed consent about the mechanism of sharing is absolutely unacceptable to me.

While I realize that Blockbuster is a business which will use what it knows about me in efforts to serve me better and make more money for itself, I had trusted Blockbuster to be sensible with this information. I did not expect that Blockbuster would conspire with Facebook to use my movie selections as an advertising mechanism to my friends without asking me about it first. I don’t really care if people know what movies my family watches, and I might have even permitted this sharing if you had asked me about it.  As a result of your decision not to respect my privacy, my trust in Blockbuster is now lost.

Therefore, I am canceling my Blockbuster subscription.

So what happened?
Well, turns out that this is a result of a new Facebook advertising feature called Beacon.  It is understandably causing quite a furor on the web; many people who realize what is going on are having the same reaction to it as I had:

Facebook's Tracking of User Activity Riles Privacy Advocates, Members
Close encounter with Facebook Beacon
Deconstructing Facebook Beacon JavaScript

In my opinion, Facebook and Blockbuster are equally at fault here.  Blockbuster should not have given my information to another entity without my informed consent.  I've fired Blockbuster.  As George Moore pointed out to me, they also seem like they are on shaky ground with respect to the Video Privacy Protection Act.

Facebook should not be inducing and facilitating this sort of information sharing without consent.  I already knew that I need to be careful with information on Facebook, so this will just raise my caution with them.  Until now, I had been impressed with the intelligent, appropriate privacy defaults that Facebook has used, but no longer.  I also liked using the principle "only put things on Facebook which I don't care if the whole world sees," but with Beacon that does not work since I don't any longer have easy control of what goes on Facebook.  I'm quite tempted to delete my Facebook profile, but that is challenging for reasons that go beyond the topics that I discuss here.

Facebook issued a press release that lists many of the companies who are disclosing your private information to them without your informed consent participating in Beacon.  It is helpful knowing which companies I need to avoid patronizing. 

Disclaimer: this post represents entirely personal opinions, not the position of Microsoft or any other entity.