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.