Privacy has its advocates. Jeff Jarvis has made himself an advocate for publicness. In Public Parts: How Sharing in the Digital Age Improves the Way we Work and Live, the original Internet optimist argues that if we become too obsessed with guarding all personal information on the ‘Net, we’ll miss important opportunities that come with making information available.

It’s a refreshing take on a topic often covered by people who feel that the Internet — and in particular, social networks like Facebook and the vast amount of personal data that flow within them — threatens to imperil our children and undermine our society. Discussions about Internet privacy often include Orwellian allusions to fear: We’re concerned about government surveillance. We don’t want targeted cookies to help advertisers track our Internet wanderings. We don’t want robbers to know when we’re not home. Sure, we want the benefits that come with the information age, but all this data about our lives that is accruing digitally? Creepy.

By contrast, Jarvis approaches these questions with delight. But before he can take down the privacy advocates, he has to offer a definition for the term. That’s not as easy as you might think. Facebook founder Mark Zuckerberg has tried to recast the desire for privacy as a desire for control over our digital identities. He argues that people want to share information, but we want to determine who gets to see and use it. Jarvis says this definition is too tidy. Privacy is much messier. We live in relationship with other people, after all. How do we even define what qualifies as our own information? If I share information that implicates you, who gets to control that?

Maybe we are looking through the wrong end of the telescope, Jarvis writes. He makes the distinction between regulating the type of information that is revealed — a never-ending game of Whac-a-Mole — and regulating how it is used — the choices people and institutions make when they are privy to someone else’s information. This is his definition of “publicness.” He then lays out a body of ethics to help think about how to respect other peoples’ data, offering some specific directives (Don’t steal information) and also more general thoughts (Motive matters). It’s worth noting that many of these rules are not so dissimilar from the cultural norms our parents taught us for how to regard privacy in the offline world: Don’t tell other peoples’ secrets.

Jarvis himself is a bit of an exhibitionist. It’s hard to imagine making some of the choices he does about what personal information enters the public domain. When he got prostate cancer, for example, he used his blog to describe his recovery process in great detail. But in return, he gathered a good deal of support from friends and strangers who empathized, recommended doctors and cheered him on. The most interesting note to this story is his explanation for how and when to share that information so it didn’t expose others in his life — his kids or his wife, for example. Radical transparency is not one decision to tell everyone everything all the time, but rather a series of smart judgment calls.

At best, Public Parts is a reminder that when any new technology is introduced — be it the growing social capabilities of the Internet or the movable type of the printing press — the immediate reaction is often fear. Jarvis points out that the earliest books were riddled with errors. These printed mistakes could suddenly spread widely and therefore they were considered to be more dangerous to society. In 1631, printers were fined for publishing a copy of the Bible that accidentally omitted the crucial word “not” from the Seventh Commandment.

It’s a good thing we didn’t dwell too long on the typos — the mass distribution of information through printed books and papers has fundamentally reshaped the world. Jarvis would apply this reasoning to the social web. The world is complicated — and our dynamic digital fossils trail along behind us, exposing us in new ways. We will make a lot of mistakes as we develop social norms around how to treat information online. His book is not so much a rallying cry for tweeting your breakfast choices and blogging your company financials as it is a field guide for how to navigate this new technology with optimism rather than fear.