Warren Buffett joins Twitter by Colleen Leahey @FortuneMagazine May 2, 2013, 4:14 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Berkshire Hathaway CEO Warren Buffett may have his hands in over 70 companies, but there’s one frontier he has yet to traverse: Twitter. The Omaha, Nebraska-based investing guru, who doesn’t have a computer in his office, joined the social media world this morning during a conversation about women and work with Fortune senior editor-at-large Pattie Sellers. The first 140-character message Buffett shared with the Twittersphere? “Warren is in the house.”Warren is in the house.— Warren Buffett (@WarrenBuffett) May 2, 2013 Two days before Berkshire’s brk.a annual meeting, Buffett engaged in a live-streamed video chat, answering questions cultivated on Twitter with the hashtag #FortuneBuffett. The discussion follows an essay written by Buffett about the dearth of women in senior leadership roles, published exclusively in Fortune on Thursday morning. The ethical case for promoting more women is obvious, Buffett argues, but there is also a bottom-line argument. “Fellow males, get onboard,” he writes. “The closer that America comes to fully employing the talents of all its citizens, the greater its output of goods and services will be.”“This is the first social interview that Warren has ever done,” said Sellers introducing the talk. Buffett said he’d read the galleys of Sheryl Sandberg’s recent book, Lean In, and had wanted to get his thoughts on women and work out.Asked about his definition of success, Buffett said it was not defined by money but by “being loved by the people you love.” Buffett went on to say the advancement of women in the workplace is a source of optimism for him vis-a-vis the future of the American economy. “Any country that is only using half of its talent,” he said, “has a great future using 100% of its talent.” He added, “just think about what you can do when you get the whole team out there.”Sellers asked why it was only in 2003 that Buffett recruited a woman outside his family to Berkshire’s board. “I don’t have a good answer to that,” Buffett said laughing. “I treated it as my own province, I didn’t consult the board all the time. I’ve gotten a lot better since then.”Buffett said his female role models include his first wife, Fortune‘s own Carol Loomis, and former Washington Post CEO Katharine Graham.