Blanket of privacy for Facebook

Monday was Quit Facebook Day, a protest organized by members of the popular social network who were outraged over its use of their private information. Hordes of Facebook’s nearly 500 million users were supposed to abandon the site, which might have shrunk my friends list to a manageable level.

But Facebook struck first, unveiling a new privacy policy last week, along with a collection of tools, which at last makes it fairly easy for Facebook users to protect their most sensitive personal data.

A user generally wants to share at least some information with the rest of the Facebook community — his or her name and sex, for instance. So that data are always made public. The same goes for the user’s photograph, if one is posted, and membership in “networks,’’ which are communities on Facebook. There’s a network for people who’ve graduated from Boston University, for example, and one for people who’ve worked at The Boston Globe. Join such a network, and Facebook will make your membership public.

But under the new policy, you can cast a blanket of privacy over the rest of your data and doings. You have to take action, as Facebook still reveals a lot of this information unless you press the right buttons.

Until last week, Facebook would always reveal a user’s favorite “pages,’’ which are sites devoted to particular tastes and interests. You might join a page for fans of gun control, for example, and Facebook would inform the world of your opinion.

That was perhaps Facebook’s worst privacy blunder, but the company has seen the light. Your favorite pages are still visible by default, but you can now change the setting so that only your friends can see your favorite pages, or so that nobody but yourself can see them. The same goes for your geographical data. The old Facebook would always disclose the user’s hometown and the city of residence; today, you can conceal that data.

In most other cases, Facebook has not changed its privacy settings. Instead, it’s made it much easier for the user to understand and modify them. Say you don’t want anybody to have access to a complete list of your Facebook friends. There’s long been a way to conceal this, but it was difficult to find and to use. The new Facebook privacy page makes it easy.

There’s also a handy way to shut down Facebook applications, the little programs you can run from inside the site, like the games Mafia Wars and Farmville. These applications collect your personal information, but you can now disconnect them with a single click. But Facebook apps also collect data about the user’s friends. If your pal subscribes to an app, the company that made it can obtain your biographical data, your birthday, and even whether you’re logged onto Facebook at that moment.

The new privacy setting lets you block 13 different categories of data shared by Facebook apps used by your friends. You must select each category separately. Facebook should let you block all 13 with a single mouse click, but this is a minor flaw in an otherwise well-designed feature.

Facebook has also added a defense against a creepy idea that ignited recent privacy protests. Just last month, the company announced a new and troubling feature called “instant personalization.’’ Users who logged into certain websites would automatically share their Facebook data with the operators of those sites. Imagine if every online retailer could instantly learn your birthday or hobbies, without asking you. That bright idea didn’t sit at all well with privacy-loving users, so Facebook now offers a kill switch that instantly disables instant personalization.

Despite all the improvements, you can’t take Facebook privacy for granted. The service reveals lots of sensitive information by default, so don’t assume that your secrets are under wraps. Go into the privacy settings and make sure.

Of course, you could just delete certain facts from your Facebook profile. Or you could join the Quit Facebook movement. Only about 35,000 people actually signed the pledge, just a few thousandths of a percent of all Facebook users. Maybe we really don’t care so much about privacy after all. Or maybe Facebook has begun to convince us that it does care.

Hiawatha Bray can be reached at bray@globe.com.