@Barack Obama is Obama’s personal Twitter page now run by his campaign offshoot, Organizing for America. Obama uses the account on occasion, using the sign-off’ –bo’ to denote tweets by him.
To follow an account on Twitter an authorized user must take the affirmative step of clicking on the follow button on their home page or next to their name and avatar if suggested by Twitter. Ignorance is not available as a defense for this one.
—Courtesy of Pat Dollard