On June 20, 2006, EFF filed an amicus brief arguing that a battle between Internet real estate services over copyrighted images should not threaten the rights of users to surf webpages and send emails anonymously.

The case began when CoStar, a real estate information database, subpoenaed LoopNet, an online real estate forum, over copyrighted photographs that appeared on LoopNet's service. The Fourth Circuit Court of Appeals already rejected CoStar's direct copyright infringement claims against LoopNet. But now CoStar has demanded not only the identification of the uploaders of the offending images, but also identification of "downloaders"—using a dangerously broad definition that includes both those who simply view the photos online and those who merely email links to the photos to others.

If upheld, this subpoena would pierce the anonymity of virtually anyone who has ever received, forwarded, or clicked on a link to a webpage that happened at one time to contain a thumbnail of a photograph to which CoStar owns the copyright. The subpoena could serve as a dangerous precedent that any copyright holder could wield against users of countless websites and services, including Google, Amazon, and eBay.

EFF's brief responds to CoStar's motion. Regardless of whether LoopNet has information on "downloaders," the chilling effect of this subpoena power would be severe, threatening constitutionally protected rights of individuals to speak, read and associate anonymously on the Internet.

On August 4, 2006, a magistrate judge denied CoStar's demands on the grounds, making it unnecessary to address EFF's arguments.

This is EFF's amicus brief in support of Loopnet, Inc. requesting that the court adopt the "Sony Plus" test for evaluating subpoenas under Section 512(h) of the DMCA and that it deny CoStar's motion to compel.