And of course, there's the never-ending issue of Facebook's privacy settings. Time and again we learn that some chunk of data is shared by default, which is to say, you've opted in unless you've explicitly opted out. That's exactly what's happening with facial recognition. Facebook has automatically opted you in, which means your friends will see suggestions of photos in which to tag you, unless you change the setting. Want to opt out? Here's how.
Given its record, what are the odds that Facebook will say no to a lucrative deal that monetizes that store of carefully-tagged photos? Even if Facebook were scrupulous about user privacy, that data store would be a very tempting target for hackers, given how fragile security at even major financial institutions appears to be these days. Can you spell "Citigroup?"
Then there's the issue of law enforcement. It is mighty easy for the feds and even local cops to get their hands on all sorts of records you might have thought were private or impossible to find. Federal officials, for example, have been grabbing location data harvested from cell phone towers for some time without getting an OK from a judge.
As I said, Facebook isn't making it possible to identify a random person by searching a database for his or her identity based on their appearance. But that doesn't mean it can't be done. Indeed, London has thousands of surveillance cameras scattered about the city and police have already found ways to match faces in those crowds with their owners.
Even assuming that our officials wouldn't do anything reprehensible with that data, what about foreign governments? Remember, Facebook has tens of millions of users outside the U.S. Wouldn't Hosni Mubarak's thugs loved to have plugged in their surveillance photos to a database and gotten the names of demonstrators in Cairo's Tahir Square?
I don't think I'm being unfair to Facebook, or acting paranoid. If I am, I have plenty of company.
The Electronic Privacy Information Center filed a complaint with the Federal Trade Commission, calling Facebook's actions unfair and deceptive: "There is every reason to believe that unless the Commission acts promptly, Facebook will routinely automate facial identification and eliminate any pretence of user control over the use of their own images for online identification."
The attorney general of Connecticut has expressed concern that Facebook facial recognition compromises consumer privacy. They are not very happy about it in Europe either, where the European Union has promised to investigate the matter.
Last week was my birthday (hold the flowers) and I was pleased when so many of my Facebook friends posted greetings on my wall. But was that good feeling really worth the risk posed by Facebook's feckless behavior? I'm not so sure.
San Francisco journalist Bill Snyder writes frequently about business and technology. He welcomes your comments and suggestions. Reach him at email@example.com. Follow Bill Snyder on Twitter @BSnyderSF. Follow everything from CIO.com on Twitter @CIOonline
This story, "Facebook Facial Recognition: Why It's a Threat to Privacy" was originally published by CIO.