Developers have been given their first glimpse of a community-funded and open alternative to Facebook.
Diaspora describes itself as a "privacy-aware, personally-controlled" social network.
It was conceived earlier this year by four US students during a period when Facebook came under fire for its privacy settings.
The open-source project has now released its first code to developers and also published screenshots.
"This is now a community project and development is open to anyone with the technical expertise who shares the vision of a social network that puts users in control," the team said in a blog.
Many of the features shown on the site will be familiar to people already on social networks such as Facebook, including the ability to share messages, photos and status updates.
The team said they are currently working to integrate the site with Facebook and to make it easy for people to take control of and move their personal data.
They aim to launch the first public product in October.
Their idea of building Diaspora started earlier this year during a period of intense criticism of Facebook, the world's largest social network.
The site, which boast 500 million members, was criticised for having overly complex and confusing privacy settings. It was eventually forced to roll out simplified controls.
"We want to put users back in control of what they share," Max Salzberg, one of the founders of Diaspora, told BBC News at the time.
The team turned to the fundraising site Kickstarter to raise funds to build the network, eventually raising $200,642 from nearly 6,500 people.
Mark Zuckerberg, the founder of Facebook, reportedly donated to the project.
The launch of the first code marks a milestone for the project. However, the team warned that there were still problems to iron out.
"It is by no means bug-free or feature-complete, but it [is] an important step for putting us, the users, in control," they wrote.
However, bugs may not be the only challenge the network faces, said Nate Elliott, principal analyst at research firm Forrester.
"It seems they are simply copying Facebook with a different architecture," he told BBC News.
"If the only differentiation is around privacy, I can't image they will persuade enough people to move away from Facebook and the network effect it has."
He said the site was a "great concept" but ideas like "data portability" were difficult to implement. However, he said, it may influence Facebook in other ways.
"Facebook has been very good at recognising what is good about their competitors and pulling in those best features."
He said the site had successfully incorporated features from Twitter and location service FourSquare.
"If Facebook genuinely see this as a threat or see that people really like it as an idea, it may influence what they do for privacy," he said.
"That would be a win for the [Diaspora] team."
Others have questioned whether there is too much expectation on the service.
"While it's possible for four talented computer scientists, in a summer, to make a piece of software that's so compelling and attention-grabbing, not just in theory but in actual use - it's also far from likely," wrote Dave Winer, a US software developer, before the code was released.