It's easy to find a reason why Facebook's email service, or much hyped Gmail-killer, won't really affect Gmail all that much: spam. How much spam do you get in your Facebook message box? I get tons. How much spam do I get in Gmail? Not a lot and if I do, Gmail's spam filter is notoriously efficient. However, technically speaking, Facebook Messages isn't designed to compete with Gmail, or is it?
Who will benefit from Facebook's new service? Heavy Facebook users looking for an integrated social networking solution. The idea is to unify all the ways that you communicate, via email, instant messging, and text messaging. There will be an unlimited conversation history, based upon each person that communicates with you. From the sound of the press release, it looks like there will be different inboxes, but all in all, it just sounds like some form of labeling, which Gmail does fine.
Spam is the enemy for anyone trying to effectively run their email. When I do get spam, I immediately mark it as such and hope to cut down on the incoming clutter. One of the reasons why I don't check my Facebook inbox all that much is because of the amount of trash it generates. Even after unsubscribing to many groups, I still receive a bunch of spam from them. Luckily, none of this is forwarded to my Gmail inbox.
Facebook Messages is modeled after chat, not email. While this sounds pretty cool, didn't Google's similar product, Google Wave, utterly fail in this regard? Ultimately, the only reason why it will work is because it's tied in directly to your Facebook account, making it simple for many people to use this. In the end, it seems like Gmail does this stuff already and in a very efficient manner, which is why we're a bit dubious about this service, but only time will tell how good it really is.
Facebook Messages is opt-in, and you can do so here. For now, the service is invite only, but we expect all users who decide to join to receive a '@facebook' email account tied to their username.