Salon is reporting that the original (sealed) order was signed on December 14th by Judge Theresa Buchanan in Alexandria, Va. It gave Twitter 3 days to comply with the DOJ without notifying anyone involved. Then mysteriously, and possibly because a gag order on a 2703 (d) might be unconstitutional, Buchanan decided this Wednesday to unseal the document at Twitter's request.
Cnet political corespondent Declan McCullagh tells TechCrunch that this is highly unusual, "So the judge — remember, a magistrate judge, not a district judge — got nervous and backed down and coughed up this week's order. You rarely see judges reverse themselves so thoroughly."
The WikiLeaks Twitter account has also mentioned Google and Facebook as other possible recipients of data requests. I have contacted both companies for more information and have yet to hear back.