Directories -- located in your Salsa headquarters under the Website Management tab -- are one of the more poorly-understood features in Salsa.
Directories, quoth our documentation, "are a tool that allow you to make a portion of your Salsa supporter list searchable through a public-facing web page. They're a unique type of page: most Salsa forms write the user's information into the database as an input. Directories enable your users to query and extract information out of the database."
Salsa user Rob McCausland of the Alliance for Community Media recently got wind of this hidden gem and ran with it; he's taken his own directory setup experience and contributed an extensive writeup to our user support site, Salsa Commons.
One of the things I love about Rob's directory is that it's so clearly programmatic. Everyone knows Salsa is great at list-building and e-blasting, but chances are your organization has bigger dreams than doing only that. Directories are a great way to serve information back to the public, and many of our users occupy a niche where they collect specialized data and serve it back to the community of stakeholders.
Here, Rob's directory indexes public access television, so the searchable data is really entities and institutions rather than individual people. There's no reason a directory couldn't be used for similarly abstract data: polling locations; Superfund sites; war criminal prosecutions since World War II; episodes of Mad Men ... you're limited only by your imagination.