Swatting down recent rumors that it's launching an e-mail killer, Facebook today unveiled a new messaging system that will envelop e-mail, instant messages, Facebook messages and SMS.

Facebook CEO Mark Zuckerberg launched what he calls a "modern messaging system" to handle the convergence of different kinds of messages and bring them together under one social umbrella. The system, which has been in the works for about 15 months, is designed to save all messages, meaning users will have a history of their communications.

Although people will now be able to have a facebook.com e-mail address, Andrew Bosworth, a software engineer at Facebook, noted that the new system will work with other e-mail systems, such as Gmail and Yahoo mail.

"People should share however they want to share," said Bosworth. "If you want to send me an e-mail and I want to get it in a text message, that should work."

At this point, the messaging system -- code-named Titan -- will not include voice chat. Zuckerberg said that should be coming down the road, but offered no timeline.

More than four billion messages are sent every day on Facebook, with the vast majority of the messages between two people, according to Zuckerberg. And about 350 million people use Facebook to message their friends and family members.

He said he started thinking about those numbers after talking with a group of high school students who told him that they rarely use e-mail. It's too slow, they told him. "I was kind of boggled by this," Zuckerberg said.

"I remember having a similar conversation with my parents about why e-mail was good and regular mail was slow...," he said. "At Facebook, we're all so used to using e-mail. It's interesting to see that all kinds of folks don't see it that way."

So Facebook decided to create a new messaging system that would include e-mail, expand on the concept and tie in other means of communication as well. "It's not e-mail," said Zuckerberg. "It handles email, in addition to Facebook messages, and IM and SMS. People are going to be able to have facebook.com email addresses but this won't be the primary way people use this system."

For the last three or four days, the Internet has been abuzz with speculation that Facebook was getting ready to launch an e-mail killer. Zuckerberg kicked off today's news event by saying that's not the case.

"There was a lot of press leading up to this saying this is an e-mail killer," he added. "This is not an e-mail killer. It's a messaging system that has e-mail as one part of it. I don't expect people to wake up tomorrow and say, 'I'm going to shut down my Yahoo account or my Gmail account.'"

"We expect that more people will IM and more people will message just because it's simpler and easier and it's more fun and valuable to use," Zuckerberg said.

Zuckerberg and Bosworth also pointed out that the messaging system doesn't exclude non-Facebook users. Users will be able to send and receive messages from people who aren't on Facebook.

The Facebook CEO also noted that the system will offer different messaging channels that gives users a social inbox and a way to get messages filtered to them from friends of their Facebook friends.

"It seems wrong that an e-mail message from your best friend gets sandwiched between a bill and a bank statement," he said. "It's not that those other messages aren't important, but one of them is more meaningful. With new Messages, your inbox will only contain messages from your friends and their friends. All other messages will go into other folders where you can look at them separately."

A few users will be invited to use the new messaging system starting today and will be rolled out to all users over the next several months.

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin or subscribe to Sharon's RSS feed . Her e-mail address is sgaudin@computerworld.com.