By adjusting its interface, Facebook has now enabled "tag suggestions" to many more of its users around the world, which means your friends will get an alert if someone uploads a photo that Facebook thinks contains your image. They'll be invited to tag it, and then your ID's associated with that image. Sounds neat in some ways, and there are a few privacy nods thrown in--Facebook notes that only friends can tag you, you'll get notified of the tag, you can remove tags and so on. But the system is actually turned on by default--which is Facebook's privacy boundary creep in action. Here's how to turn it off, with a reminder  of how to enable other privacy measures.
Under the "Account" drop-down menu at the top-right of Facebook's title bar, click "Privacy settings." On the bottom half of the next window, under "Sharing on Facebook" click "Custom." Then at the bottom, click on the little blue pencil and its "customize settings label." In the next window scroll down to the "Things others share" section and the third list item, "Suggest photos of me to friends." Click on the "Edit Settings" button, and scan to the middle right of the new pop-up window, which has little pics of your friends to remind you how friendly Facebook is. See the facility is enabled? Click on this button, select "Disabled." And then click on "OK" to make the pop-up go away.
Easy, wasn't it? Just nine click/scroll maneuvers required to burrow through multiple layers of windows.
While you're there on the privacy page, check a few other things too:
Things you share
Check this list, which starts with "Posts by me" and ends with "Places you check in to" and verify that the status is "Friends only," which is as tight as you can set these (although you can customize the settings to prevent particular friends from accessing each of the shred items on a granular level). Disable the "Include me in 'People here now' after I check in" button to make sure you don't appear associated with a Facebook Place.
Then click through to "Edit privacy settings for existing photos and videos" to double check you're not sharing pics and videos with everyone--I found that I had been, even though I wasn't aware of the fact, so it's worth a check.
Things others share
Same trick here for the shorter list that starts with "Photos and videos you're tagged in," ends with "Friends can check me in to places" and includes the new Face Recognition trick. All of these can be restricted to Friends only, and you may want to pay attention to the "Friends can check me in..." button if you're protective of your location data. If you like, you can lock your wall so friends can't write on it.
This may be one that you'd most like to protect. Double check the settings for your address, IM screen name, and email addresses say "Friends only," and note that by selecting "custom" from each button's drop-down menu you can set it to "Only me" for highest privacy.
You're all done! Sort of. Click "back to privacy settings" to make more changes.
Connecting on Facebook
This page controls how your information is searchable on Facebook--it's worth checking that each item in the list corresponds to how open or locked-down you want to be. Check "search for you on Facebook" and restrict it to "friends only" if you want to control how many friend requests you get. And double check other items like "see you current city..." and "see your likes..." are correctly set. Several of mine weren't, and I'd not visited this page in a while.
Click "back to privacy" for yet more changes...
Apps and websites
This is where you manage which parts of your data the apps you use can access and share automatically, what info about you your friend's friends can see, and how much of your Facebook profile is shown up when people Google for your name. Check all of these (it gets laborious if you want to go into each app's settings) and pay special attention to "public search," which is where you give search engines permission to crawl your data.
From the main Privacy settings page, here's where you can target specific Facebook users and limit their access to you.
And....you're done. Easy wasn't it?