I have 666 friends on Facebook. By next week, I hope to have none.

I am going to spend this week “unfriending” all of my Facebook friends because I have come to believe that Facebook cannot provide me the level of privacy that I need. And yet, I am not quitting entirely because I believe that as an author and a journalist, it is important to have a Facebook presence.

My specific concern with Facebook is what NYU Professor Helen Nissenbaum calls a lack of “contextual integrity,” – which is a fancy way of saying that when I share information with a certain group or friend on Facebook, I am often surprised by where the data ends up.

Professor Nissenbaum argues that many online services – of which Facebook is simply the most prominent example –share information in ways that violate the social norms established in offline human relationships.

For example: In real life, even if I am friends with someone, I don’t necessarily want to join their book group or cooking group etc. But on Facebook, my friends can join me to a group without my permission, and my membership in that group is automatically made public.

This is no small thing: this exact feature is what caused two University of Texas students to be outed to their parents, when the president of the Queer Chorus joined them to a Facebook group.

Although I am not worried about being outed, I am a journalist who needs to protect my sources, my relationships and my affiliations from public scrutiny. I am also, quite simply, a human who doesn’t want to be shocked by information about myself that I cannot control. And so, I plan to spend this week unfriending all my Facebook friends.

I did not come to this conclusion easily. I have long struggled with the right approach to Facebook.

I joined Facebook on June 26, 2006, back when it was still only available to people with university e-mail addresses. In fact, I signed up for an alumni address from my college just for the purpose of joining Facebook.

My motivation was primarily journalistic: I was researching a book about the social network MySpace and needed to understand the social networking landscape. But I also enjoyed the thrill of reconnecting with friends from high school and college.

But like many Facebook users, I felt burned when in December, 2009, Facebook unilaterally changed all users’ default privacy settings to encourage sharing information to the entire world instead of just ‘friends.’ My list of friends was automatically made public – which is a terrible problem for journalists who may have befriended sources that could be betrayed by disclosure of the relationship.

Outraged, I wrote a column declaring that Facebook had betrayed the confidential nature of friending, and that I was going to treat it as a public forum like Twitter. I opened up my profile entirely; I began accepting all friend requests (even really creepy ones) and scrubbed my profile clean of any personal details. (Facebook later agreed to settle charges brought by the Federal Trade Commission, which alleged that Facebook’s actions were unfair and deceptive).

The technical name for my approach to Facebook was “privacy by obscurity.” By burying good data (my actual relationships) amidst bad data (people I didn’t know), I aimed to shield my relationships from unwanted scrutiny.

However, privacy by obscurity made Facebook almost unusable. My news feed was cluttered with updates from people I didn’t know. Many of my new ‘friends’ were joining me to groups and sending me spam. Slowly but surely, I started using Facebook less and less. Last year, I didn’t post a single update all year.

Now I am researching and writing a book about online privacy, Tracked, to be published next year. In my book, I aim to answer two questions: why does privacy matter? And what should we do about it? To answer the second question, I’ve been trying out several privacy-protecting measures, such as blocking Web tracking technology and setting up new online identities.

But I’ve been struggling to figure out what to do about my long-neglected Facebook account. My privacy by obscurity approach had only netted spammers and made Facebook annoying to use.

I considered trimming my friends list to a bare minimum (as Fred Wilson successfully did), but I realized that I don’t actually keep up with my closest friends and family on Facebook (we use email, texting and phone).

I considered giving up on privacy by obscurity and actually using Facebook to keep up with people I know. But that would require me to trust Facebook to protect my list of friends. I dug around on Facebook’s privacy settings, and found that it still doesn’t allow you to completely protect your list of friends. If you share a friend with someone, your mutual friend will be displayed to both of you.

For a journalist, even that amount of disclosure is too much: Imagine a low-level employee of an institution who befriends a journalist to share information. If official spokesman for that same organization notices that he or she shares a “mutual friend” with a journalist, that disclosure amounts to outing the employee as a source. So that argued against reducing my list of friends to people with whom I actually have a relationships.

I considered just deleting my profile. But I realized I was going to miss three things about Facebook: 1) I like being able to be send private messages to people through Facebook when I don’t have their latest contact information; 2) I like being notified when I’m tagged in a photo or in a post (usually so I can request being untagged); and 3) As a journalist and author, I would like to be ‘found’ by people who want to read my writing.

And so I’ve decided to unfriend everyone and keep a bare-bones profile for the simple purposes of messaging, untagging and being found by people who might want to find me.

For those who I am unfriending, apologies in advance. As bizarre as it sounds, I am actually trying to protect the contextual integrity of our relationship.

I’m very excited to share with everyone the announcement of my new book, which was posted on Publishers Marketplace this week:

Wall Street Journal senior technology editor and author of STEALING MYSPACE Julia Angwin’s TRACKED, investigative journalism on the importance of understanding and preserving electronic privacy in the age of social media and pervasive surveillance by marketing firms, retailers, credit monitors, government agencies, and snoops of all kinds, to Paul Golob at Times Books, at auction, by Todd Shuster at Zachary Shuster Harmsworth Literary Agency (NA).