Facebook announced Monday that it is building a full-fledged e-mail system into its 500-million-member social network. Facebook CEO Mark Zuckerberg said the new e-mail offering will be introduced over the next couple of months to users.

Zuckerberg said e-mail is just one part of the new, converged messaging system called Facebook Messages. The system blends e-mail, Facebook messages, SMS, and chat in one interface, so that users can receive and send messages in whatever form is appropriate. Facebook's users will be able to get an @Facebook.com e-mail address that will allow them to communicate with any email account outside the Facebook network.

The messaging offering has been created from the ground up and is not just an improvement of Facebook's existing limited Messaging system. Facebook also announced that a new iPhone app will be released to facilitate the new messaging service. Facebook has had 15 engineers working on the project for a year, Facebook engineering director Andrew Bosworth says.

Core Elements



Te service has the following three core elements.

Seamless messaging: Ability to communicate with people inside and outside of Facebook using e-mail, Facebook messaging, IM and text messaging using multiple devices, including mobile ones.

Conversation history: Conversations between two people aren't broken up under different subject headings, but rather are collected as one long, ongoing thread.

Social inbox: In a feature that other e-mail systems can't match, Facebook is using your Facebook data to figure out which e-mails and other messages are important to you, and which ones aren't so important. It organizes high priority messages in special folders. It's a similar algorithm used with the news feed to put the most important people and content on top.

Facebook Messages will slowly roll out over the next few months, on an invite system, the company says. Users will see a notice at the top of the existing messaging page inviting them to reserve their new Facebook email address. "Vanity" Facebook URLs, like www.facebook.com/marksullivan will turn into e-mail addresses, like marksullivan@facebook.com.

Zuckerberg says the messaging service can speak to all other e-mail clients, but does not yet support IMAP.

Messaging Extends Beyond Facebook

With the ability to communicate with people outside the Facebook system, Facebook will be capturing e-mail addresses and other information that didn't already exist on its servers. Zuckerberg acknowledges this, but says that information is being captured to make the messaging tool smarter and easier to use. He denies that the information collected via Facebook's messaging platform will be used to target ads, or shared with advertisers or marketers, or made accessible to Facebook app makers.

Watch Out, Google

The move makes sense; it's simply the latest volley in Facebook's war with Google to be the place where people spend most of their time on the Internet. Google currently owns this honor, but Facebook has proved that its addictive service can hold people's attention for long periods of time. In terms of Internet advertising and marketing, this is extremely valuable.

Zuckerberg says the new messaging system is not meant to be a "Gmail Killer"--not yet anyway. "We don't expect people to wake up tomorrow and shut off their Gmail account. We expect in a month or in a few years, people to say ‘Hey, this is the way that messaging ought to be done.'"

Facebook is clearly trying to match all the services Google provides around its core search capability. Beyond its messaging capabilities, you can also already share links, photos, and video clips as well. There's an instant messaging chat tool. A partnership with Skype allows you to make voice calls from the platform; Google only recently added this capability to Gmail. E-mail is the piece that has been obviously missing, and now it is here.

We will be getting a look at the actual Facebook e-mail client later this morning, and will report back with more details.

There is certain to be more privacy discussion around this move, as Facebook begins hosting our e-mail data at its servers. What new information from our e-mail will Facebook collect and add to our social graph? But it's the same old bargain: are you willing to give up a little more of your privacy in exchange for a free and convenient new service?