Not everyone would think that actor Ashton Kutcher’s Twitter musings on his daily doings constitute part of “the universal body of human knowledge”–but the Library of Congress now does, reports the New York Times. The 210-year-old guardian of knowledge and cultural history will archive the collected works of Twitter, the micro-blogging service whose users currently send a daily flood of 55 million messages–all containing 140 or fewer characters. Library officials explained the agreement as another step in its embrace of digital media. Twitter, the Silicon Valley start-up, declared it “very exciting that tweets are becoming part of history”–and academic researchers seem pleased as well. For hundreds of years, they say, the historical record has tended to be somewhat elitist because of its selectivity. In books, magazines, and newspapers, they say, it is the prominent and the infamous who are written about most frequently. Although celebrities like Kutcher might have the most followers on Twitter, they make up a tiny portion of its millions of users. “This is an entirely new addition to the historical record, the second-by-second history of ordinary people,” said Fred R. Shapiro, associate librarian and lecturer at the Yale Law School…