Yahoo to turn subscribers' e-mail contact lists into social networking base

Yahoo plans to announce Tuesday that it is jumping into social networking by using its massive population of e-mail subscribers as a base for sharing information on the Web.

Over the next few weeks, its 280 million e-mail users will be able to exchange comments, pictures and news articles with others in their address books. The program won't expose a user's contact list to the public, as was done by Google through its social networking application, Buzz. But unless a user proactively opts out of the program, those Yahoo e-mail subscribers will automatically be part of a sweeping rollout of features that will incorporate the kinds of sharing done on sites such as Facebook and MySpace. The plan could spark criticism from Yahoo e-mail users, who signed up for the free service perhaps never imagining the people they e-mailed would become friends for sharing vacation videos, political causes and random thoughts throughout the day.