As expected, Facebook on Monday announced an email-related service that it will roll out to users over the coming months. However, rathan than a completely new service, it is instead an update to Facebook's existing Messages service.

The new Messages service does go well beyond the email capabilities that were expected, adding free cell phone texting, instant messaging (IM), and non-Facebook email access. And it looks, in many ways, very much like AOL's previously announced Project Phoenix. Of course, coming from a service with more than 500 million users, Facebook's new service will likely reach far more people.

But the most interesting aspect of the revamped messaging service is that email is being downplayed as a tier-one experience because it's just too slow and is unlike the other, more immediate ways that people communicate today. "If we do a good job, some people will say this is the way the future will work," Facebook Founder Mark Zuckerberg said during an event announcing the changes. "We don't think a modern messaging system is going to be email."

For now at least, Facebook will allow users to consolidate email through the service's Messages service, and then add the ability to send and receive email from facebook.com accounts. (Facebook's own employees will be moving to the fb.com domain.) Facebook will use its understanding of users' so-called "social graph," or real-world relationships, to bubble the most important email to the top of the inbox.

According to Zuckerberg, about 350 million of the service's 500 million users actively utilize today's Messages service, which is a walled garden of sorts inside the broader Facebook. This compares with 362 million unique Hotmail users, 273 million Yahoo! Mail users, and 193 million for Gmail, according to comScore's latest numbers.

As is always the case with Facebook, privacy advocates were quick to condemn the service's move into more pervasive messaging. "This opens up another door that allows it to closely track how their members communicate," Jeff Chester, executive director of the Center for Digital Democracy, said. "It's deeply disturbing."