Facebook rolled out an all-in-one messaging service that for the first time allows its half-billion members to communicate with people outside the social network, intensifying a battle with Google Inc and Yahoo Inc for users' Internet time.
Addressing speculation the world's largest social networking site was planning a "Gmail-killer," Facebook Chief Executive Officer Mark Zuckerberg said the new system will let users own "@facebook.com" addresses, but stressed it went beyond mere email.
The new feature - to be rolled out over coming months - lets users send and receive instant and text messages in addition to standard email and Facebook notes.
"This is not an email killer. This is a messaging system that includes email as one part of it," Zuckerberg told reporters at the St. Regis hotel in San Francisco.
Zuckerberg, who said more than 350 million of Facebook's half-billion users now actively send and receive messages on his website, did not expect people to stop using traditional email tomorrow.
But he hoped more and more will shift to an integrated, cross-platform mode of communications over the longer term, such as the service he debuted Monday.
Analysts say that email users are particularly valuable to Web portals like Yahoo, which seek to funnel the traffic into their other online services.
Facebook and Google's intensifying rivalry is expected to play a crucial role in shaping the future of the Internet. The industry is closely watching their pitched struggle for Web surfers' time online, advertising dollars, and increasingly costly Silicon Valley talent.