The library says it began archiving tweets “for the same reason it collects other materials – to acquire and preserve a record of knowledge and creativity for Congress and the American people.” The archive stretches back to Twitter’s beginning, in 2006.

But as anyone who’s been following along can attest, Twitter and the way it’s used has changed since then. First and foremost from a collection perspective: the sheer number of tweets.

“The volume of tweets and related transactions has evolved and increased dramatically since the initial agreement was signed,” the library explains in a white paper accompanying the announcement.