One of the factors that makes Twitter so addictive is the fleeting, transient nature of the tweet: shortly after appearing online, your 140-character post will be more or less forgotten, consigned to oblivion.

That is about to change, however, with the announcement that Twitter is to become the “official social network of record” now that the U.S. Library of Congress, the world’s largest library, has acquired the entire Twitter archive. According to the LoC blog, the library will archive every tweet ever posted by Twitter’s 105 million users, a tally numbering in the billions. The acquisition will add to the LoC’s already extensive collection of “born digital” materials. From the LoC blog:

[I]f you think the Library of Congress is just books, think of this: The Library has been collecting materials from the web since it began harvesting congressional and presidential campaign websites in 2000.  Today we hold more than 167 terabytes of web-based information, including legal blogs, websites of candidates for national office, and websites of Members of Congress.