You bought it, you own it.

That's a concept we've been fighting to defend for years against erosion at the hands of patent and copyright owners, in contexts as diverse as printer cartridges, promo CDs, and software. The answer should be simple—if you bought it, a copyright or patent owner shouldn't be able to use federal intellectual property law to dictate whether you can resell it, simply by pointing to boilerplate in a license agreement or label. That's thanks to the "first sale doctrine" (also known as "exhaustion").

Today EFF, joined by national library associations, the Consumer Federation of America, Public Knowledge, and U.S. PIRG, filed an amicus brief in Vernor v. Autodesk, the latest battle to raise the question of whether the "first sale doctrine" will continue to have vitality in a world filled with end-user license agreements that claim that you own nothing, but rather merely "license" it. The appeal pits eBay seller Timothy Vernor against software giant Autodesk. When Mr. Vernor tried to auction four authentic, packaged copies of AutoCAD software, Autodesk sent DMCA takedown notices to block his auctions and threatened to sue him for copyright infringement. Mr. Vernor, assisted by the lawyers at Public Citizen, took Autodesk to court and won.

Autodesk has appealed, arguing that so long as its license agreements recite the right magic words, it can strip purchasers of any ownership in the CD-ROMs on which software is delivered. If that's right, then not only don't you own the software you buy, but any copyright owner can simply recite the magic words and effectively outlaw libraries, used bookstores, and DVD rentals, among other things (eBay also filed an amicus brief on behalf of Mr. Vernor). That would be bad news not just for consumers looking to save a few dollars, but also for our ability to access older, out-of-print materials. For these materials, often libraries and second-hand sellers are the only hope for continued public access.

This appeal is one of three pending before the Ninth Circuit that touch on "you bought it, you own it" issues. Along with EFF's pending petition with the Copyright Office to permit iPhone jailbreaking (which also turns on what rights you have as a software owner), these three cases promise to have a substantial impact on the shape of the "first sale doctrine" in the digital age.