As expected, Facebook CEO Mark Zuckerberg unveiled the social network’s “next generation messaging” system yesterday, and the highly anticipated announcement underscores both the key role email plays in today’s communications and the implicit need for social media and email to work hand in hand.

The new messaging service, which will roll out gradually after an invitation-only start, will focus on seamless messaging, conversation history across multiple channels, and a "social inbox" that can filter the inbox to only allow messages from “friends.”

The announcement, coupled with AOL’s Project Phoenix unveiling on Sunday and similar expected inbox enhancements by Yahoo, MSN and Google, confirms that we’re seeing a movement toward a single messaging inbox.

So, with more than 500 million Facebook users, what impact will the social network’s new messaging system—and the similar iterations from others referenced above—have on marketers?  Here are seven areas marketers will need to pay careful attention to moving forward:

1) Brand name/subject line: With Facebook doing away with subject lines, “From” names and brand ID become even bigger in determining whether recipients ignore, delete or open your message. Now’s the time to revisit your “From” name and make sure it’s the shortest, most logical, most recognized brand that would make sense to subscribers and that they