By Tobias Carroll Presidential libraries vary dramatically, depending on the president in question. Over the course of researching a book about political signs, I had reason to interact with the staff of several. (The Eisenhower Presidential Library was especially helpful.) Some libraries focus on the legacies of their namesake; others abound with historical items that offer insight into their lives and times. What, then, can we expect from the presidential library for the nation’s 44th head of state? The website for the Barack Obama Presidential Library currently houses abundant archives from…