Thanks for this interesting paper. I think the "article lifecycle" perspective is a useful one, complementing the various "social media guide for scientists" (scientist, not paper, point of view) out there.
One observation: the paper seems to suggest the science/scientist's presence in social media will be through the scientist directly interacting with and generating content into the social networks. I would say that in many cases it will be more likely or sensible for this dissemination to occur through mediation of other parties/systems, such as publishers or peers or journalists/communicators.
I explore these possibilities in a post from January, "How To Bring Academics to the Social-Media Party? Indirectly." (http://tjm.org/2013/01/14/how-to-bring-academics-to-the-social-media-party-indirectly/).
Strong, direct social-media engagement involves significant learning, time, risk, and particular skills. I'm not convinced we can, should, or need to expect a large portion of scientists to devote this effort, given all the other demands on them. In many cases, intermediaries may taken on parts of this -- just as they do the running of journal platforms, scholarly societies, conferences, etc. I think social media should and gradually will be just woven into many existing activities and tools: in the words of Mark Weiser, "the most profound technologies are those that disappear."
@tmccormick / http://tjm.org / Palo Alto, CA, USA