if you don't want the service sharing things about you automatically with everyone you know Facebook launched some fairly impressive new features and services at its recent f8 conference, but some of them were also more than just a little scary.
Since a lot of what the company talked about was introduced either in "developer speak"—involving such terms as API and JSON—or involved social networking jargon such as "social graph" and "activity map," we thought it would be handy to break it down for those who aren't as well-versed in such things. What should you do if you don't like the prospect of automatically sharing your activity with everyone you know on Facebook? 
Liking without logging in:
The biggest change Facebook has launched will let any Web site you visit display a simple "like" button, for example on a story at CNN.com—although CNN has decided to use the term "recommend" instead. If you click that button, it will show all your friends on Facebook that you liked that story by posting it on your Facebook wall. It will also show you—in the same box on the CNN (TWX) site that has the "recommend" button—how many of your friends liked that story.
Note: The most important aspect of this feature is that CNN and other sites will be able to do this without you logging in with a user name and password and without you clicking any Facebook Connect buttons. All that is required is that you have signed in to Facebook at some point before you visit the site.
Instant personalization:
As my colleauge Liz Gannes explained in her Apr. 22 post, some sites will be allowed to take this ability even further, showing users personalized content based on the details of their public profile on Facebook.The company will be able to read and interpret that content without asking users. At the moment, only three sites have this extra ability, which Facebook calls "instant personalization"—they are Docs.com (an online document-hosting and editing site from Microsoft), the music site Pandora, and the review site Yelp.
Note: The important thing to note about this feature is that it is opt-in by default, which means it is turned on automatically—and you have to specifically turn it off if you don't want these services to read your profile and customize their services for you.
What should you do?
The easiest way out of all these new features is, of course, simply not to log in to Facebook or to deactivate your account. To do the latter, you have to go to this page, down at the bottom, and click "deactivate."
Note: Doing this doesn't actually cancel your Facebook account; it simply hides it. As Facebook explains on its help pages, "your profile and all information associated with it are immediately made inaccessible to other Facebook users.What this means is that you effectively disappear from the Facebook service.However, if you want to reactivate at some point, we do save your profile information (friends, photos, interests, etc.)." If you actually want to delete it, you have to go here.
But what if you don't want to cancel your account? Then you can do one of several things:
- • Turn off instant personalization: Uncheck the box at the bottom of this page. This will prevent Facebook from allowing Pandora, Docs.com, and Yelp to show you customized content based on your Facebook details.
But as the site Librarian By Day explains, this won't prevent your friends from sharing certain data about you with those services. And how do you stop that?
- • Block those applications: If you don't want any information to be shared with those specific apps, either by you or by your friends, you must specifically block each and every one of those apps (luckily, there are only three so far).
You can control which applications are allowed to share your data, as well as what your friends can share about you, on this page. All your privacy settings—such as what turns up when people search for you, whom you have blocked, and so on—can be controlled on this page.
- • Don't click the "like" button at any of the sites you visit: This will prevent you from sharing that information with your Facebook friends, or having it show up on your wall, and sites won't be able to send updates to your news feed.
