The Google+ social network launched with much fanfare at the end of June. As the 100-day mark approaches, Google is looking to further expand the audience. The search giant is now dropping the invitation barrier and making the service accessible to all users. 
 
 In a statement on the official company blog, Google engineering senior vice president Vic Gundotra explained that the site is ready to move from "field trial" to full beta. Google+ has adequately scaled with the growth of the audience so far—it's not clear how many users connect to the site every day, but Gundotra says that over a billion posts have been shared since the launch. 
 
 In addition to allowing anyone to sign up for the service, Gundotra also announced other new features that are going to roll out on Google+ over the next few days. The Hangout feature, which enables multiuser video chat, is going to be supported on mobile devices via the native iOS and Android applications. Google is also expanding Hangouts in the browser, offering integration with Google Docs and screensharing. 
 
 Alongside these changes, Google is also starting to open up APIs to third-party developers. They have started by enabling programmatic read-only access to public user posts. Not enough functionality is exposed through the APIs yet to support a full-blown third-party desktop client, but it's not a bad start. Google is also working on APIs for Hangouts, which will make it possible for third-party developers to integrate their own services with the video chat system. 
 
 In our own experiences with Google+, we found that the granular sharing model helps differentiate the service and will likely give it staying power. It's already off to a better start than Buzz, which was plagued with privacy problems and didn't offer much innovation out of the box. ||||| Final update: Three months after ReadWriteWeb first described these plans in detail, Google announces Google Circles as part of a larger social initiative. It is as we reported it. 
 
 
 
 We believe that Google will preview a major new social service called Google Circles at South by Southwest Interactive today. Update: Google has now officially denied that Circles will launch here, but not that it exists. See final update below, as of afternoon Texas time Google does now deny that Circles exists. If what we've heard is correct, the service will offer photo, video and status message sharing. Everything users share on Circles will be shared only with the most appropriate circle of social contacts in their lives, not with all your contacts in bulk. Circles may be shown off at an event co-hosted tonight by the ACLU, an organization focused on privacy and the liberties it affords. It may not be a big public launch yet, but it's clear that this is a major product in the works at the very least. Please see below the fold for what I hope will be the final update on this for now. 
 
 The service has been developed with extensive participation by Chris Messina, the co-creator of numerous successful social and software phenomena online, from BarCamp to Hashtags and much more. Messina declined to comment for this story. Jonathan Sposato, CEO of the photo editing service Piknik that Google acquired last year, is working on Circles as well. Sposato may be the only entrepreneur to have sold not one but two startups to Google - having founded Phatbits, a service that was acquired by Google in 2005 and became Google Gadgets. These are heavy hitting tech leaders and the service should be very interesting. 
 
 Google's response. Google is now telling Liz Gannes at the technology blog All Things D that there is no product being developed. That's a real shame, if that's the truth of the matter. 
 
 Gannes writes: 
 
 
 
 When a report emerged this morning of a new social network focused on nuanced sharing called Google Circles, the company said it was not launching anything this week at SXSW. But such a product is not even under development, according to the people supposedly developing it. Google's Chris Messina, who had been pegged as one of the leaders of Circles, told me directly today that he "didn't know what [the story] was talking about." 
 
 A trusted source with credible information, among several conversations I've had, lead me to draw the conclusions I did. I tried to frame them with some cautious caveats, but now Gannes is being told something different. To be honest, this wouldn't be the first time I've been told that a story I broke "was not based in fact" only to see something pretty darned close get confirmed later. I guess we'll see about this one. 
 
 There's plenty of evidence indicating that Circles is very real, of course. For example, one RWW reader found that if you look at the Buzz tab on a Google Profile with no linked media accounts, the page reads "nothing shared, try adding more people to your circles." 
 
 And now to return to our previously posted report. These details may in fact be a picture of what Google is going to do. They may instead be simply what Google ought to do. Take your pick, we'll know in time, I suppose. 
 
 A Matter of Personas 
 
 With Circles, I believe that Google will attempt to accomplish something critics from the blogosphere, academia, SXSW 2010 keynoter danah boyd, privacy watchdogs and others have all called on the social networking world to do: to allow our online communication to respect the same boundaries that our offline social lives do. 
 
 School and work, friends and family, the sacred and the profane; we've always been able to communicate different things to different people in different circumstances. Facebook, Twitter and other online social networks have collapsed all those contexts into one big bucket. We speak to our "friends" all at once, no matter what we might want to say to one group of people or another. And thus we often feel less comfortable than we might saying anything at all. 
 
 This fundamental discomfort has been, many people argue, a limiting factor in the growth, reach and depth of online social interactions. If that problem could be solved, there are big new ways that the online world could grow and evolve. This has been a more sophisticated understanding of privacy, not just as a public/private dichotomy but as a matter of contextual integrity of communication, that we and others have been calling on Facebook to adopt for almost two years. 
 
 The development of Circles is likely heavily influenced by the work of ex-Google social technology researcher Paul Adams. Adams has written a book called Social Circles, which will be released this Summer and he published a widely read slide deck about what is wrong with social networking: specifically the lack of respect for context and personas. (The Real Life Social Network) Adams worked on User Experience at Google for four years, but just months after publishing his influencial presentation he left Google for Facebook. 
 
 Courting Developers 
 
 Given who is working on it, I expect that Google Circles will be as developer friendly as other Google social products, but with a much greater emphasis on design and usability. 
 
 Messina and Sposato both have strong backgrounds in working with developers and APIs. Messina was trained as a visual designer and created the full page ad in the New York Times announcing the launch of Firefox, then went on to become a leader in the open web community. His work has included co-creating the international unconference phenomenon called Barcamp, helping build OpenID federated identity system, leading the Activity Streams movement for an interoperable social network user activity data system and initiating the use of #hashtags on Twitter. When he joined Google in January 2010, we wrote extensively about his life and career. 
 
 Right: Messina posted this photo on Foursquare today of posters promoting Google's hacker event at SXSW. 
 
 It is nearly inconceivable that Messina would be involved and the effort wouldn't be a standards-based platform play. If Circles is unveiled at SXSW, the timing couldn't be better from a developer relations perspective. Google can position itself as going exactly the opposite direction Twitter is. Twitter saw its biggest outpouring of criticism yet when it told developers on Friday that they should not build any more basic interfaces, clients, for using Twitter. It remains to be seen how that will play out, but if a major social network wanted to try to lure developers to build on their platform, this could be a good time to start talking about it. 
 
 Google Tries Again 
 
 Google has launched many different social efforts over the years but has remained far behind Facebook and Twitter in its efforts. Social networking is an important technology for Google to find success with as it's a key way that people spend time online and that targeted advertisements are delivered to those people. 
 
 Google Buzz felt overbearing and bolted on. It also got privacy terribly, terribly wrong. Google Wave was more confusing than collaborative. Google's Open Social interoperable widget platform was hugely hyped as a distributed Facebook killer, but it now primarily focused on enterprise social networks. 
 
 Reports emerged last June that Google has been working on a secret social project called Google Me. 
 
 In December a screenshot was leaked to TechCrunch showing a new toolbar item on Google.com called "Loop." (Loop seems similar to Circles - I think Circles is better.) I believe that Circles will be a toolbar level service as well. 
 
 It's hard to think of a stronger angle to take than support for contextual integrity of communication and conversation, of personas in social networking. 
 
 Google has tried and failed in many other (though not all) social efforts. Bringing some of the best thinking and the best innovators in the world to a new effort to tackle one of the world's biggest problems is very ambitious. 
 
 Presuming that the things we're hearing are true (I believe they are), then we'll follow up with in-depth coverage of Google Circles once it's launched. That may be tonight, it may be as far in the future as the Google IO developer conference in two months - but I believe we are going to see at least some parts of it today. More clear than the timing is that this is definitely happening: Google is putting some of its most innovative social thinkers behind a major product called Circles and focused on personas.
– If you’re one of those poor, sad souls who couldn’t get a friend to hook you up with a Google+ invitation, good news: It's your lucky day. As of yesterday anyone can sign up for Google’s social networking service, Ars Technica reports. Google still considers the service a work in progress, “but with the improvements we’ve made so far we’re ready to move from field trial to beta,” a senior VP wrote on the company blog. Google has also added a variety of new features, including the ability to search for specific posts and people, and a host of new features for its “Hangouts” video chat function. You’ll now be able to access Hangouts from Android phones, for example, and you’ll be able to name them, integrate them with Google Docs, and more.