Bush and Cheney thought so, but some Justice Department officials said they were illegal.
The nation has elected a black man as president, but that hasn't erased deep-seated racism or economic inequalities.
Congressional Twitterers include Sen. John McCain, who last year said he didn't know how to use e-mail. But don't look for tweets from President Obama.
His race may hamper his ability to respond to needs of African-Americans, some say.
South Korea said Friday it had identified and blocked five IP addresses used to distribute computer viruses that caused a wave of Web site outages in the U.S. and South Korea.
Leaders agreed that warming must be stopped, but few specifics were reached on how to reduce greenhouse-gas emissions.