Facebook rolled out an all-in-one messaging tool that pools users' email, instant and text messages, taking on Google's and Yahoo's popular email platforms.
Facebook Chief Executive Officer Mark Zuckerberg said the new system will give users their own "facebook.com" email addresses and let them send instant and text messages in addition to standard email and Facebook notes.
"These are the three things that we think create a modern messaging system: seamless integration across all the different ways that people communicate, including email, but not only email.
"A single conversation history so you can have all your context with friends and people that you know all in one place, simple to interact with and communicate through. And the third is a social inbox for filtering exactly the messages that you want to see."
Addressing speculation the world's largest social networking site was planning a "Gmail-killer" refering to Google's email service Zuckerberg said the two tools could co-exist.
"Email is still really important to a lot of people and we just think that this simpler kind of messaging is going to be how a lot more people shift a lot of their communication."
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 users' time online.