Stuff like this is why I'm proud to be on EFF's Advisory Board. (Although I can claim zero credit for EFF's great work on this matter.)
Here's a part of EFF's intro to the report linked above:
We at EFF, like the public at large, are often left in the dark about what the government's practices in this area look like. However, sometimes — just sometimes — the fog will clear and we'll get a worrisome picture of what the government gets up to behind closed doors. Sometimes this happens when an independent-minded judge publishes an opinion revealing the government's practices, like the judge that first revealed that the government was tracking cell phones without warrants. Other times, someone served with an SCA demand such as a National Security Letter comes to us for legal assistance.
Recently, one such recipient of an SCA demand did come to us, and we're glad she did. The story of that subpoena — to the administrator of www.indymedia.us, an independent activist news site aggregating stories from Indymedia web sites across the country — provides yet another example of how government abuses breed in secrecy. Hopefully this analysis will be helpful to other online service providers who receive such bogus requests masquerading as valid legal process.