These days, it’s old news that government officials can pry into Facebook and other websites as part of their investigations. But it’s still unclear what exactly they must do to get access to sites like Facebook in the first place: can they demand information about hundreds of people all at once? And does Facebook have a right to challenge the warrants on behalf of its users?

Now, some answers are on the way. On Thursday, five judges of a New York court agreed to hear an appeal of a sweeping order from July that forced Facebook to turn over information about 381 accounts at once in a controversial “bulk warrant” process. And significantly, the judges also gave permission to a group of outside companies and organizations — ranging from Google to Kickstarter to the ACLU — to participate in the proceedings.

“We are pleased that the Appellate Division will hear this important appeal concerning vital Fourth Amendment protections against overreaching data requests. We look forward…