A s a candidate, Barack Obama harnessed the power of social-media sites such as Twitter, Facebook and YouTube. So it’s no surprise that his administration recently set up official profiles for the White House on these sites and more. But being friends with the White House on MySpace isn’t the same as “friending” your college roommate. It’s one thing when your friends see pictures of you drunk at school or read a post speculating about whether you have the swine flu, but it’s quite another when officials at the White House can see that.