Yahoo hopes to drive more traffic to its sites by allowing people to share information about their interests and activities with friends. Like on Facebook, they'll be able to create a network of connections and send alerts to those people when they upload photos to Flickr or comment on a story at Yahoo News, for example.
The platform will extend to non-Yahoo sites such as Amazon and Digg, so that users will be able to see from within Yahoo's Web sites what their friends have been doing elsewhere on the Web. And third-party sites will be able to publish user activity back into the Yahoo network, which could help those sites draw more visitors.
The search company is making the data it stores about users -- such as their contacts, interests and location -- available for developers to build their applications. End users will be able to regulate which of their information friends and developers can see, said Yahoo officials, who previewed the platform in San Francisco on Friday.
It's an ambitious project that required Yahoo to "rewire" its properties to create a single underlying platform that connects them all. Those services existed in the past as "silos" that allowed for little interaction between them, said Ash Patel, executive vice president with Yahoo's Audience Product Division.
"The platform is how we start rewiring and reforming the user experience," he said.
Yahoo launched the first piece of the puzzle last week, a site called where end users can manage their activities, interests and social connections in one place. Next week will mark the launch of the developer component. It's built on top of Yahoo's existing network infrastructure and consists broadly of three layers.
The first is the Yahoo Social Platform, a repository where Yahoo stores the personal data about its users, along with their "social graph," or information about who their friends are. Above that is the Application Platform, which provides the development framework. And above that is the Yahoo Query Language, which developers will use to pull personal user data from Yahoo's servers and write their programs. YQL is very similar to the widely used SQL database language, according to Yahoo.
The platform also makes use of public APIs such as , for aggregating user data from other social networking sites, and , a protocol for consuming and publishing personal data. The tools and documentation will be available for free download next week from the Yahoo Developer Network, said Jay Rossiter, head of Yahoo's Open Strategy project. He wouldn't say exactly which day.
Yahoo officials gave examples of the types of applications it wants developers to build. If a person receives an e-mail telling them it's a friend's birthday, an application could allow them to view their friend's Amazon.com from within Yahoo Mail. Another program might automatically upload photos received via Yahoo Mail to an online photo account, be that Flickr or a non-Yahoo service such as Shutterfly.
Part of the challenge will be getting Yahoo's users to buy into the idea. At some time in the future, when they log into a Yahoo service they'll see the Yahoo Activator, which will present a list of all their contacts pulled from Yahoo Mail, Yahoo Messenger and other services. They'll use this to build their connections list and decide who can see what information.
Activations can already be done at the new Yahoo Profiles site and with a beta of Yahoo Messenger 9 that was just released. Activations will be rolled out more widely in a few months when the option is presented to people when they log into their Yahoo Mail accounts, and at other Yahoo services after that.
Each new application will have to warn users about the data it plans to access, such as their address book, inbox or profile, and about who the information will be shared with. Patel admitted that this is a delicate area. Yahoo will make certain selections by default that users can then alter.
"Choosing the right defaults so people don't inadvertently give away their privacy is part of the challenge," Patel said.
The OAuth protocol allows users to give a site access to their data for a limited time, such as two weeks, said Neal Sample, a Yahoo chief architect.
Yahoo doesn't expect the Profiles page to become a major destination. Instead, users will eventually be able to install applications and display updates at their My Yahoo page, in Yahoo Mail, and possibly at Yahoo's main home page.
Yahoo, which has been struggling to sustain its growth rate, hopes the social networking features will encourage people to use more of its services. If the average user visits two or three of its sites today, it hopes that seeing what friends are doing elsewhere in its network will prompt them to visit four or five sites in the future, Patel said.
Yahoo spent the past year developing the platform. Much depends now on the creativity of developers to make it a success, Patel said.