After archiving the entirety of public tweets from Twitter’s inception in 2006, the Library of Congress has decided to change its strategy for collecting and preserving tweets for posterity, by switching to a more event-based strategy that collects around elections or issues of ongoing national interest.

The Library of Congress and Twitter initially came to an agreement in April 2010 that would provide the Library with the company’s public tweet text from Twitter’s inception in 2006 to the date of the agreement. Twitter agreed to provide future tweets on an ongoing basis under the same terms.

According to a Library of Congress update on their policy, the Library saw an opportunity to document the emergence of social media, and sought to establish a secure process and organizational structure for receiving an ongoing stream of tweets.

“The Library continuously reviews its ongoing acquisitions, whether subscriptions to newspapers or the receipt of tweets via a gift. As a result of the review, the Library has determined that its initial Twitter collection will consist of a twelve-year snapshot of the beginning of one of social media’s most important and transformative communication tools. Subsequent selective tweet collecting may continue in addition to the 12-year snapshot,” the update said.

According to the update, the policy change was made because the volume of tweets is increasing, the size of those tweets has expanded and the Library’s text-only agreement with Twitter means that many visual-centric tweets limits the value of that collection style. The update also added that the 12-years of already collected tweets adequately documents the rise of an important social media platform.

“Throughout its history, the Library has seized opportunities to collect snapshots of unique moments in human history and preserve them for future generations. These snapshots of particular moments in history often give voice to history’s silent masses: ordinary people,” the report said.

“The Twitter Archive may prove to be one of this generation’s most significant legacies to future generations. Future generations will learn much about this rich period in our history, the information flows, and social and political forces that help define the current generation.”

The Library of Congress’ new policy will go into effect Dec. 31, 2017. According to the update, there is no projected timetable for providing public access to the twitter archive at this time.