CEDAR RAPIDS — Tom Vilsack, who admitted he was computer illiterate while serving as Iowa’s governor for two terms, has joined social media.“40+ years as a public servant and I’m finally sending my first tweet! Honored to serve our nation once again alongside USDA’s dedicated public services,” the recently confirmed Secretary of Agriculture posted on Twitter Wednesday afternoon.By Thursday morning he had tweeted two more times — in reply to President Joe Biden and Vice President Kamala Harris.Vilsack, who served as USDA secretary for eight years during the Obama administration, was confirmed 92-7 by the U.S.