There's a common misconception among website owners that they are not responsible for content that others post on their website. The truth is that, although it is possible for website owners to shield themselves from liability, there are certain hoops they need to jump through first. And if you don't take those steps before someone posts infringing content, you can find yourself on the hook for it.
The prerequisite step is designating a copyright agent for your website. The Digital Millennium Copyright Act (DMCA) establishes a "safe harbor" for website owners that protects them from liability for material that third parties post to the site. Specifically, 17 U.S.C. § 512(c)(1) provides that
Importantly, however, 17 U.S.C. § 512(c)(2) says that websites can only claim this protection if they have designated a contact person to receive takedown requests, and listed that person's information on both the website itself and with the Copyright Office:
The filing fee for the designation form is approximately $150.
A July 2014 opinion in the case Oppenheimer v. AllVoices, Inc., a judge in the Northern District of California reiterated that website owners remain on the hook for third-party content on their sites, unless and until they comply with these agent designation requirements.
Have you designated an agent for your website yet? It's a worthwhile step that can save you an enormous amount of time, expense, and headache down the road.