Suggestions or requirements? In June of last year, new legal ethics guidelines developed by the Commercial and Federal Litigation Section of the New York State Bar Association addressed new guidelines for social media practices.
As reported in the NYLJ, an attorney was sanctioned over $7000 by a federal court "by directing her law clerk to create a false identity, use that false identity" to attempt contact with a represented party and/or witness. Although not clear from the article, it appeared that the false identity may have been utilized through various forms of social media.
See http://www.newyorklawjournal.com/this-weeks-news/id=1202767300023/Judge-Sanctions-Attorney-For-Investigating-ExOfficer?mcode=1202615036097&curindex=2&slreturn=20160814063901