Twitter this week said it's donating its digital archive of public tweets to the Library of Congress, which has long gathered people's firsthand accounts of history before there were social networks to do so.

Twitter processes more than 50 million tweets per day and has become a de facto archive for people to log the daily events of their lives. The service has become especially relevant when people witness events that take on public or even global significance -- such as the recent earthquake in Haiti -- as people use it to provide updates as they happen.

Before there was Twitter or Facebook, however, the Library of Congress acted as an archive for people's accounts of history. Contained in its archives are "man on the street" interviews after Pearl Harbor and a documentary of firsthand accounts of 9/11.

The library will now add billions of public tweets dating back to Twitter's inception in 2006 until the present time to its archive, it said in a press statement.

The Twitter archive will not be posted online, but the Library said it may gather tweets related to special topics or events that have historical significance and post them as a collection.

For instance, the library has archived personal stories of war veterans in the Veterans History Project, and could create similar online archives from the Twitter material, it said.

The Library of Congress began collecting Web material in 2000, when it gathered information from congressional and presidential campaign Web sites. It currently has more than 167 terabytes of Web-based information, which includes legal blogs and Web sites for Members of Congress.

The Library also leads the National Digital Information Infrastructure and Preservation Program, a congressionally mandated program that collects and preserves significant digital content so future generations have access to it.