If you have ever requested documents through PACER, you need to know about RECAP.  RECAP is a project of the Center for Information Technology Policy at Princeton University.  The RECAP site describes the project:

RECAP is an extension (or “add on”) for the Firefox web browser that improves the PACER experience while helping PACER users build a free and open repository of public court records. RECAP users automatically donate the documents they purchase from PACER into a public repository hosted by the Internet Archive. And RECAP saves users money by alerting them when a document they are searching for is already available from this repository. RECAP also makes other enhancements to the PACER experience, including more user-friendly file names.

In other words, every time you retrieve a document from PACER with the RECAP extension enabled in Firefox, a copy of the document is provided to the RECAP database.  When another RECAP user requests that same document in the future, the RECAP database will offer to supply the document free of cost.  It's a form of viral assistance, and it's brilliant.  It costs nothing and serves a laudible public purpose.

Get the extension at the RECAP site.  While you're there, you can read up on the extension.