In the aftermath of last week's Facebook versus Gmail battles, Facebook announced today that it is launching its own message system, but it's not your average email product. Facebook Messages is designed to "feel like a conversation," and marketers may be interested to know that socially-targeted ads on the Facebook site will perform the same way in Facebook Messages threads across platforms.

Facebook officials explained in a live event today that users can have an @facebook.com email address, but the messaging system is more like chat than email. Information can be shared across channels in seamless messaging.

Users can talk to friends via chat, email, Messages or SMS (the Facebook iPhone app is also launching today). Notably, communication can happen via non-Facebook email accounts. Facebook founder Mark Zuckerberg says this user-friendly feature won't require senders to decide which technology to use – based on previous conversations or recipients' online availability, the smart product will send messages accordingly.

Facebook Messages makes it easy for users to search for relevant conversations in their inboxes in order to inform current messaging. The new conversation history tools expand on Facebook's wall-to-wall capabilities that enable two Facebook users to see relevant intra-site posts. The company has rebuilt its conversation structure to enhance documentation across platforms.

Zuckerberg says the Facebook messaging system is a "social inbox" that has a filtering edge because of the site's social graph. Facebook can perform extreme filtering based on the information that users share with the site. The more personalized or relevant messages are to a user, the more priority they get in an inbox – marketers take note.

This is not an "email killer," but a messaging system that includes an inbox, according to Zuckerberg. He doesn't expect people to cancel their Gmail or Yahoo accounts tomorrow … but he does hint that he thinks users will decide simpler, more social messages are the way of the future.

While this may be "the future of online communication," it has significant relevance at present. There are 350 million people who actively use Facebook messaging, and more than 4 billion messages are shared through the Facebook system on a daily basis. Marketers who carefully plan content to send to Facebook fans may boost their message standing in users' Facebook inboxes and get their share of mentions among the millions that take place daily.

As reported in the Facebook blog, Facebook Messages will be rolled out gradually, and available to all users in the next few months.