For all of Google's successes, the company has an underwhelming track record when it comes to social networks. Time after time, its attempts have been met with shrugs or downright hostility. An early offering called Orkut languished in obscurity (unless you live in Brazil). Wave, a real-time messaging system, proved too confusing for most users. Last year saw the release of Buzz, an attempt to build a social network based on users' Gmail contacts. It was introduced with much fanfare and seemed to be Google's best opportunity to dispel the critique that social wasn't in its DNA.

But Buzz was an embarrassing debacle. The service publicized users' contacts without asking permission, causing customers and critics to recoil. Though Google addressed those problems, the initial taint stuck; Buzz is technically still Buzzing, but the service is nowhere near the social powerhouse the company had envisioned. Worse, its initial flaws led to a rebuke from the Federal Trade Commission. Ultimately, Google agreed to submit to privacy oversight for the next 20 years.

Now Google is back with Google+, a new and even more ambitious social service. Fifteen months in the making, the sweeping initiative attempts to make sharing and communicating an integral part of Google's entire array of offerings—search, Gmail, YouTube, Maps, and so on. Unlike Facebook and Twitter, where every update usually gets shared with everyone, Google+ makes it easy to direct messages to specific groups of people, thanks to its now-celebrated Circles feature. In addition to its Facebook-like stream of updates from friends, family, and colleagues, Google+ also includes an "interest stream"—called Sparks—with shareable items automatically culled from the Net that pertain to your favorite topics. Another feature, Hangouts, lets users instantly create a videoconference with up to 10 friends.

Ever conscious of its past failings, the Googlers had braced for a skeptical reception when Google+ was introduced as a "field test" in June. Instead, it was met with unbridled enthusiasm. "We knew pretty quickly that we were onto something," says Vic Gundotra, Google's senior vice president of social initiatives. "It was just amazing to see the activity." A few weeks later, Google announced that 10 million people had signed up for the service. By August, estimates pegged the Google+ population at about 20 million. (Google wasn't saying.)

The positive response was sweet vindication for Bradley Horowitz, Google's vice president of products. As head of Buzz, he had seen firsthand how a social product launch could go horribly awry, and as a lead developer on Google+, he was keen to avoid repeating those mistakes. But Horowitz—an MIT Media Lab alum and former rock guitarist and Yahoo executive—says his team isn't taking any victory laps yet. (Compared with Facebook's global carnival of 750 million users, Google+ is just a sideshow off the midway.) But although the service is still being developed, Horowitz says it could eventually transform the whole company. We sat down with him to ask how.

Wired: What was the launch like?

Horowitz: It's a bit of a blur. We'd spent a lot of time inoculating the team against the inevitable sniping. Then we got this really positive response. But the sugar can be a lot more insidious than the vinegar. It's harder to ignore, and you can start believing the hype. So we just encouraged everyone to put blinders on and stay focused on the long term.

Wired: How was working on Google+ different from working on the company's previous offerings?

Horowitz: Until now, every single Google property acted like a separate company. Due to the way we grew, through various acquisitions and the fierce independence of each division within Google, each product sort of veered off in its own direction. That was dizzying. But Google+ is Google itself. We're extending it across all that we do—search, ads, Chrome, Android, Maps, YouTube—so that each of those services contributes to our understanding of who you are.

Wired: What have you learned about how people are using Google+?

Google+ is extremely privacy-sensitive and considerate. Those lessons were visceral and hard-won.Horowitz: We've found there is actually twice as much private sharing as there is sharing that's visible to everyone on the Internet. That's why sometimes it looks like people sign up and then don't come back. In fact, they're sharing with small groups of people that they trust and love. It's just not publicly visible. So there's this sort of dark matter that the public can't see.

Wired: What sorts of problems are people having?

Horowitz: There are two different kinds of experiences. There are the early adopters who are carefully curating their circles. The biggest challenge they face is what we call the noisy-stream problem, in which a few active people overwhelm the conversation. We need some tools to either suppress that noise or present the information in a way that it doesn't dominate.

But there's another class of users who are having an empty-stream problem. Either they have not added enough people to their circles, or they have not yet connected to the people that they care about. They're just not engaging and not visiting enough. We have plans in place to address both ends of that spectrum.

Wired: You call this a field test, but Google+ very quickly attracted 10 million users, and by now it's many more. How big does it get before you have to say it's real?

Horowitz: We refer to it as a limited field trial, and it's limited in several ways. First, apart from the initial seed group, every user has been invited by another user. You need to know somebody in the system to get into the system. But the other sense of the word limited is that what you see now is not the entirety of the feature set.

Wired: What can we expect to see in the future?

Horowitz: Google+ introduces a new means of sharing, and one of the things that people love to share is media. People are already sharing fun media on the service, like animated GIFs. We're not ready to announce anything now, but I think you can extrapolate and say Google+ is a good way to share mass media as well. That could take the form of people listening or watching something together in Hangouts.

Wired: Have you thought about how you're going to make money off this?

Horowitz: It's not the highest priority. And it would be premature to come up with that before we understand how it's used. But if we do a good job of serving users, we can stick to the Google philosophy that ads are a kind of tax on the product. So, for example, if you and I are talking about where we're going for dinner on Sunday, and the system is smart enough to recognize the nature of that discussion and offer me a 20 percent discount for a local restaurant, that's not a nuisance. That's an incredibly valuable offer.

Wired: Some users are chafing at Google's insistence that they provide real names. Explain the policy against pseudonyms.

Horowitz: Google believes in three modes of usage—anonymous, pseudonymous, and identified, and we have a spectrum of products that use all three. For anonymity, you can go into incognito mode in Chrome and the information associated with using the browser is not retained. Gmail and Blogger are pseudonymous—you can go be captainblackjack@gmail.com. But with products like Google Checkout, you're doing a financial transaction and you have to use your real name.For now, Google+ falls into that last category. There are great debates going on about this—I saw one comment yesterday that claimed that pseudonyms protect the experience of women in the system. I felt compelled to respond, because I've gotten feedback from women who say that the accountability of real names makes them feel much more comfortable in Google+.

Wired: I've heard reports that, after the initial boom, usage has leveled off or declined.

Horowitz: Most of those stories are based on wrong data.

Wired: So it's not leveling off?

Horowitz: We don't want to get into the game of reacting to every story. That would be a huge distraction. We have our own dashboards, which give us a very clear indication of how the system is behaving and what we need to do to improve it. We have a really strong sense of where we're going, and enough validation that the snarkiness is not damaging. And while we're flattered by the early growth, acquiring users has never been an explicit goal for our field trial.

Wired: Now that Google+ has been so well received, do you feel the company has debunked the charge that it doesn't understand social networking?

Horowitz: Yes. I think that was never true. We've had successes and failures in the social space, but I think that blanket charge was unfair. That wasn't the reason behind those successes and failures.

Wired: It must be particularly gratifying after the Buzz disaster.

Horowitz: I firmly believe that we would not be where we are today with Google+ but for the lessons we learned in Buzz. Google+ is extremely privacy-sensitive and considerate. Those lessons were visceral and hard-won.

Senior writer Steven Levy (steven_levy@wired.com) is the author of In the Plex: How Google Thinks, Works, and Shapes Our Lives.