Although Facebook messaging was announced last year with the caveat “This is not an email killer.“, just one glance at the rest of the discussion and the charts tell you that email will be drastically different if not dead were the Unified Messaging to be successfully and broadly adopted. But to achieve broad adoption, Facebook needed more than, well, Facebook. Rockmelt is a very good start toward a better answer–not only to the limitations imposed on Facebook by browsers at present, but to the general problem of social activity stream integration.
Gmail has already shown that the browser can compete and even improve on the experience of old school mail environments like Outlook/Exchange. Rockmelt aims to show that the social experience — twitter, RSS, Facebook, etc — can thrive and improve within the browser.
Just as Facebook redefined “friend,” I expect that Facebook Unified Messaging and its competitors will be redefining “email.” You might be using the same word, but it won’t mean the same thing and you won’t interact in the same ways as before. email in name only is #noemail and that’s a good thing too.