Yahoo and Facebook have announced a link-up that will allow people to log into any Yahoo website using their Facebook details.
The partnership marks a significant milestone for the Facebook Connect service, which is already used by a number of sites including CNN and Yelp.
“This increases Facebook’s prominence as a big part of the social infrastructure of the web,” Ray Valdes, an analyst with Gartner, told the London Financial Times.
At the same time, Facebook is increasing promotion of its Connect facility, which allows its 350 million users to log into other sites using their Facebook ID.
By allowing users to log into different websites, taking their network of friends with them, Facebook hopes to provide users with an identity they can use across a range of sites.
“The social dimension is becoming a key part of the web experience,” said Mr Valdes. “It’s no longer sufficient to connect to content, we also need to connect to people.”
Yahoo is hoping that by embracing Facebook it can attract new users. The search company has been playing catch-up in social networking but has pledged under chief executive Carol Bartz to put social tools into many of its websites.
It has also attempted to become a more open platform, allowing users to customise homepages with a variety of widgets and applications.
“This will allow Facebook feed to be enriched by Yahoo content, and Yahoo to benefit from the Facebook network,” said Jim Stoneham, vice-president of communities for Yahoo.
Details of the non-cash deal are still being worked out. Yahoo said it expects to roll out the service in the first half of next year.
Already there is an overlap between the two sites’ audiences.
According to internet traffic analysts comScore, 52 per cent of Yahoo visitors are also using Facebook, while 84 per cent of Facebook users also visit Yahoo sites.
Yahoo still maintains one of the most popular collections of sites on the web. These include the photo sharing site Flickr, careers site HotJobs and its self-branded sports and finance pages.
The move also represents an attempt by Yahoo to claw back some of its influence in the web. “They were once a centre of gravity for the web,” said Mr Valdes. “That shifted.”
In the wake of a controversial deal that gave Microsoft power over Yahoo’s search engine, analysts said Yahoo could be ceding too much control.
“The risk for Yahoo is that they’re slowly giving up control of their user experience to other parties,” said Mr Valdes.