So, there's another similar case mentioned here, but related to a Reason comment: with that one the government went and got a gag order from a judge.

In this case, they just sent that "preservation letter" and in the letter said not to alert the user: Techdirt (somewhat reasonably) is portraying that as "effectively" a gag order. They didn't go on even to issue a subpoena here, and so they also didn't go get an actual gag order, but it's something they've been known to do.