Subscribe | UPI Odd Newsletter Subscribe WASHINGTON, July 26 (UPI) -- White House staffers have been blocked from using Twitter at work, press secretary Robert Gibbs said. Gibbs disclosed the block Friday, saying he doesn't use the popular social networking site himself because the world already knows enough about what he is doing, Tribune Newspapers reported Sunday. Advertisement Gibbs said he really doesn't know why the chief executive's offices blocked access to the site. Maybe to avoid taxpayer-funded tweets, Tribune Newspapers said. President Barack Obama reportedly posts on two Twitter sites: @WhiteHouse and @BarackObama.