Bill Clinton sent only two e-mail messages as president and has yet to pick up the habit. George W. Bush ceased using e-mail in January 2001 but has said he’s looking forward to e-mailing “my buddies” after leaving Washington, D.C. Barack Obama, though, is a serious e-mail addict. “I’m still clinging to my BlackBerry,” he said in a recent interview with CNBC. “They’re going to pry it out of my hands.”