A little more than two years ago, the Library of Congress announced it would preserve every public tweet, ever, for future generations.

That’s right. Every public tweet, ever, since Twitter’s inception in March 2006, will be archived digitally at the Library of Congress. That’s a LOT of tweets, by the way: Twitter processes more than 50 million tweets every day, with the total numbering in the billions.

Fifty million tweets a day. How cute. That number is now 400 million, according to Twitter CEO Dick Costolo. (The first comment on the project’s FAQ page sums up much of the Internet’s reaction: “It’s critical the future generations know what flavor burrito I had for lunch.”)

We hadn’t heard about this project in some time. Last week a story on Canada.com quoted a social-media researcher as saying the LoC “has quietly backed away from the commitment.”

False, said Library spokeswoman Jennifer Gavin; the project is very much still happening. Good librarianship, she said, moves more slowly than Twitter.

“The process of how to serve it out to researchers is still being worked out, but we’re getting a lot of closer,” Gavin told me. “I couldn’t give you a date specific of when we’ll be ready to make the announcement.”

The Library first revealed its plans in a tweet on April 14, 2010, but apparently that was before sorting out with Twitter the logistics of acquiring all that data. Petabytes of data.

“We began receiving the material, portions of it, last year. We got that system down. Now we’re getting it almost daily,” Gavin said. “And of course, as I think is obvious to anyone who follows Twitter, it has ended up being a very large amount of material.”

Gavin said the archive will be made available to anyone with a library card, but only on the premises in Washington. “My understanding is that at this time we do not intend to make it available by web,” she said, but that may be subject to change. It’s not meant to be the Ultimate Twitter Search Box we’ve always dreamed of.

In fact, there will be a six-month embargo on fresh tweets (even though, obviously, the data is publicly available — if you can find it). That agreement has been in place since the deal was struck. Twitter said then the tweets could be used only “for internal library use, for non-commercial research, public display by the library itself, and preservation.”

The challenge now is finding ways to refine the raw data in useful ways. Sort by keywords? Date? Sentiment? Burrito flavor? Gavin said the Library is still figuring out the user interface.