I lamented the lack of a specific NLM social media presence as recently as February: PubMed. The Twitter account I was told was not official (see comments) for months now is. See the complete list of official NLM social media channels at http://www.nlm.nih.gov/socialmedia/index.html
Even better, there is a Friends of the National Library of Medicine (FNLM) conference being held April 6-7th entitled The ePatient: Digital and Genomic Technologies for Personalized Healthcare that is making use of the Twitter hashtag #eNLM. This may not seem all that remarkable but things have come a long way from a total lack of NLM presence in social media less than a year ago to a dedicated webpage of social media channels, and their news account on Twitter promoting a conference hashtag:
Being the librarian/archivist type that I am, I discovered no one else created the wthashtag wiki page for the conference so I did. Learn what’s being discussed, see who the main participants are, and run transcripts by selecting date ranges at http://wthashtag.com/Enlm
I wish I wasn’t on the other side of the country and could be there, and hopeful that those who are will share the wealth of information with the rest of us!