The way I read it, this new type of messaging will only replace a part of why you use email, the part where you communicate with friends. The other part will r

The way I read it, this new type of messaging will only replace a part of why you use email, the part where you communicate with friends. The other part will remain unchanged, and email would eventually become much more like snail mail is today -- a formal medium for communicating important notices, like bills or legal actions. The new Facebook messaging system would sort of merge all of your communications to/from friends over email/IM/SMS into one type of much more informal communication.