This excellent article discusses the liability of nonprofits when third parties post infringing material to their websites.
The Digital Millennium Copyright Act (DMCA) provides that those who own websites can be liable for all material posted to their websites that infringes the copyright of another person. This includes websites that allow third parties to post to their websites. However, the DMCA’s “safe harbor” rule allows website owners to avoid liability if they follow certain procedures, as outlined in the above article.
If you are a nonprofit and you allow third parties to post content to your website, this article is a must read.