a new messaging service -- what Mark Zuckerberg called a "modern messaging system," not a new email system. Email's "too formal," according to Zuck, and the new system is designed to be seamless, simple, and short in comparison. "We think we should take features away from messaging -- it should be simple." All that said, it'll handle email and users can have facebook.com email addresses, but it also integrates SMS, IM, and Facebook messages -- Zuck doesn't think email will be the primary way people use the system, and your conversation history will integrate messages from across various services into threads. Facebook is also doing what it calls a "social inbox," which sounds like Gmail's priority inbox on steroids -- it uses your Facebook contacts list to automatically build whitelists for important messages. Unfortunately, there's no IMAP support at launch, so you won't be able to plug in your favorite mail client, but it's coming, says Facebook. The new messaging system should be rolling out slowly over the next few months -- hopefully Facebook will come out with a pithier name than "new messaging system" by the time everyone gets it.