Already home to the UK's most iconic national documents from the last millennium, The National Archives is expanding its digital collection by going social. It's begun archiving tweets and YouTube videos published by the UK's ruling parties over the last decade, permanently preserving them as the official public record. Unlike in the US, where the Library of Congress has set about archiving all of America's tweets (and has already collected more than 170 billion messages), the National Archives' sights are firmly set on government accounts. While that may include mundane social updates from the Forestry Commission, HM Revenue and Customs and the Office of Fair Trading, the Archive will also preserve moments of national pride: events including the 2012 London Olympics, the birth of Prince George and the Queen's Diamond Jubilee have all been saved in the digital vault. Right now, the collection includes 7,000 YouTube videos and more than 65,000 individual tweets -- it has the capacity to collect 3,200 tweets at any one time, though, allowing you to trawl announcements of past environmental heath issues, premium bond interest rates and possibly a future British Wimbledon winner at your leisure.