Social media has become increasingly integrated into political strategies, particularly since the beginning of the 2012 election cycle, and now the White House has opened an official Twitter account for the First Lady of the United States. The @FLOTUS account is currently run by Michelle Obama's office, with tweets officially sent by Obama herself signed "-mo." It's distinct from her personal Twitter account, just as Vice President Joe Biden has separate personal and official accounts (@JoeBiden and @VP respectively), meaning it will likely be passed down as new women — and theoretically men, though the acronym would no longer apply — succeed Obama. President Barack Obama still uses a single Twitter account, though there's an official White House Twitter feed.
As figures like the Pope join Twitter, there's a rise of accounts that are tied not only to major political leaders but to political offices themselves. It's also another platform for the semi-formalized work done by First Ladies, including Michelle Obama's anti-obesity effort — social media is a highly appropriate venue for the kind of soft power the President's spouse is supposed to have.